"File name too long" error for file locks
Snap, encountered when trying to run [this example from PyTorch Lightning Flash](https://lightning-flash.readthedocs.io/en/latest/reference/speech_recognition.html):

```py
import torch

import flash
from flash.audio import SpeechRecognition, SpeechRecognitionData
from flash.core.data.utils import download_data

# 1. Create the DataModule
download_data("https://pl-flash-data.s3.amazonaws.com/timit_data.zip", "./data")

datamodule = SpeechRecognitionData.from_json(
    input_fields="file",
    target_fields="text",
    train_file="data/timit/train.json",
    test_file="data/timit/test.json",
)
```

Gave this traceback:

```py
Traceback (most recent call last):
  File "lf_ft.py", line 10, in <module>
    datamodule = SpeechRecognitionData.from_json(
  File "/home/louis/miniconda3/envs/w2vlf/lib/python3.8/site-packages/flash/core/data/data_module.py", line 1005, in from_json
    return cls.from_data_source(
  File "/home/louis/miniconda3/envs/w2vlf/lib/python3.8/site-packages/flash/core/data/data_module.py", line 571, in from_data_source
    train_dataset, val_dataset, test_dataset, predict_dataset = data_source.to_datasets(
  File "/home/louis/miniconda3/envs/w2vlf/lib/python3.8/site-packages/flash/core/data/data_source.py", line 307, in to_datasets
    train_dataset = self.generate_dataset(train_data, RunningStage.TRAINING)
  File "/home/louis/miniconda3/envs/w2vlf/lib/python3.8/site-packages/flash/core/data/data_source.py", line 344, in generate_dataset
    data = load_data(data, mock_dataset)
  File "/home/louis/miniconda3/envs/w2vlf/lib/python3.8/site-packages/flash/audio/speech_recognition/data.py", line 103, in load_data
    dataset_dict = load_dataset(self.filetype, data_files={stage: str(file)})
  File "/home/louis/miniconda3/envs/w2vlf/lib/python3.8/site-packages/datasets/load.py", line 1599, in load_dataset
    builder_instance = load_dataset_builder(
  File "/home/louis/miniconda3/envs/w2vlf/lib/python3.8/site-packages/datasets/load.py", line 1457, in load_dataset_builder
    builder_instance: DatasetBuilder = builder_cls(
  File "/home/louis/miniconda3/envs/w2vlf/lib/python3.8/site-packages/datasets/builder.py", line 285, in __init__
    with FileLock(lock_path):
  File "/home/louis/miniconda3/envs/w2vlf/lib/python3.8/site-packages/datasets/utils/filelock.py", line 323, in __enter__
    self.acquire()
  File "/home/louis/miniconda3/envs/w2vlf/lib/python3.8/site-packages/datasets/utils/filelock.py", line 272, in acquire
    self._acquire()
  File "/home/louis/miniconda3/envs/w2vlf/lib/python3.8/site-packages/datasets/utils/filelock.py", line 403, in _acquire
    fd = os.open(self._lock_file, open_mode)
OSError: [Errno 36] File name too long: '/home/louis/.cache/huggingface/datasets/_home_louis_.cache_huggingface_datasets_json_default-98e6813a547f72fa_0.0.0_c2d554c3377ea79c7664b93dc65d0803b45e3279000f993c7bfd18937fd7f426.lock'
```

My home directory is encrypted, therefore the maximum length is 143 ([source 1](https://github.com/ray-project/ray/issues/1463#issuecomment-425674521), [source 2](https://stackoverflow.com/a/6571568/2668831))

From what I've read I think the error is in reference to the file name (just the final part of the path) which is 145 chars long:

```py
>>> len("_home_louis_.cache_huggingface_datasets_json_default-98e6813a547f72fa_0.0.0_c2d554c3377ea79c7664b93dc65d0803b45e3279000f993c7bfd18937fd7f426.lock")
145
```

I also have a file in this directory (i.e. whose length is not a problem):

```py
>>> len("_home_louis_.cache_huggingface_datasets_librispeech_asr_clean_2.1.0_468ec03677f46a8714ac6b5b64dba02d246a228d92cbbad7f3dc190fa039eab1.lock")
137
```
## Describe the bug

Getting the following error when calling `load_dataset("gar1t/test")`:

```
OSError: [Errno 36] File name too long: '<user>/.cache/huggingface/datasets/_home_garrett_.cache_huggingface_datasets_csv_test-7c856aea083a7043_0.0.0_9144e0a4e8435090117cea53e6c7537173ef2304525df4a077c435d8ee7828ff.incomplete.lock'
```

## Steps to reproduce the bug

Where the user cache dir (e.g. `~/.cache`) is on a file system that limits filenames to 255 chars (e.g. ext4):

```python
from datasets import load_dataset
load_dataset("gar1t/test")
```

## Expected results

Expect the function to return without an error.

## Actual results

```
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "<python_venv>/lib/python3.9/site-packages/datasets/load.py", line 1112, in load_dataset
    builder_instance.download_and_prepare(
  File "<python_venv>/lib/python3.9/site-packages/datasets/builder.py", line 644, in download_and_prepare
    self._save_info()
  File "<python_venv>/lib/python3.9/site-packages/datasets/builder.py", line 765, in _save_info
    with FileLock(lock_path):
  File "<python_venv>/lib/python3.9/site-packages/datasets/utils/filelock.py", line 323, in __enter__
    self.acquire()
  File "<python_venv>/lib/python3.9/site-packages/datasets/utils/filelock.py", line 272, in acquire
    self._acquire()
  File "<python_venv>/lib/python3.9/site-packages/datasets/utils/filelock.py", line 403, in _acquire
    fd = os.open(self._lock_file, open_mode)
OSError: [Errno 36] File name too long: '<user>/.cache/huggingface/datasets/_home_garrett_.cache_huggingface_datasets_csv_test-7c856aea083a7043_0.0.0_9144e0a4e8435090117cea53e6c7537173ef2304525df4a077c435d8ee7828ff.incomplete.lock'
```

## Environment info

- `datasets` version: 1.12.1
- Platform: Linux-5.11.0-27-generic-x86_64-with-glibc2.31
- Python version: 3.9.7
- PyArrow version: 5.0.0

"File name too long" error for file locks 
 ## Describe the bug

Getting the following error when calling `load_dataset("gar1t/test")`:

```
OSError: [Errno 36] File name too long: '<user>/.cache/huggingface/datasets/_home_garrett_.cache_huggingface_datasets_csv_test-7c856aea083a7043_0.0.0_9144e0a4e8435090117cea53e6c7537173ef2304525df4a077c435d8ee7828ff.incomplete.lock'
```

## Steps to reproduce the bug

Where the user cache dir (e.g. `~/.cache`) is on a file system that limits filenames to 255 chars (e.g. ext4):

```python
from datasets import load_dataset
load_dataset("gar1t/test")
```

## Expected results

Expect the function to return without an error.

## Actual results

```
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "<python_venv>/lib/python3.9/site-packages/datasets/load.py", line 1112, in load_dataset
    builder_instance.download_and_prepare(
  File "<python_venv>/lib/python3.9/site-packages/datasets/builder.py", line 644, in download_and_prepare
    self._save_info()
  File "<python_venv>/lib/python3.9/site-packages/datasets/builder.py", line 765, in _save_info
    with FileLock(lock_path):
  File "<python_venv>/lib/python3.9/site-packages/datasets/utils/filelock.py", line 323, in __enter__
    self.acquire()
  File "<python_venv>/lib/python3.9/site-packages/datasets/utils/filelock.py", line 272, in acquire
    self._acquire()
  File "<python_venv>/lib/python3.9/site-packages/datasets/utils/filelock.py", line 403, in _acquire
    fd = os.open(self._lock_file, open_mode)
OSError: [Errno 36] File name too long: '<user>/.cache/huggingface/datasets/_home_garrett_.cache_huggingface_datasets_csv_test-7c856aea083a7043_0.0.0_9144e0a4e8435090117cea53e6c7537173ef2304525df4a077c435d8ee7828ff.incomplete.lock'
```

## Environment info

- `datasets` version: 1.12.1
- Platform: Linux-5.11.0-27-generic-x86_64-with-glibc2.31
- Python version: 3.9.7
- PyArrow version: 5.0.0
 
 Snap, encountered when trying to run [this example from PyTorch Lightning Flash](https://lightning-flash.readthedocs.io/en/latest/reference/speech_recognition.html):

```py
import torch

import flash
from flash.audio import SpeechRecognition, SpeechRecognitionData
from flash.core.data.utils import download_data

# 1. Create the DataModule
download_data("https://pl-flash-data.s3.amazonaws.com/timit_data.zip", "./data")

datamodule = SpeechRecognitionData.from_json(
    input_fields="file",
    target_fields="text",
    train_file="data/timit/train.json",
    test_file="data/timit/test.json",
)
```

Gave this traceback:

```py
Traceback (most recent call last):
  File "lf_ft.py", line 10, in <module>
    datamodule = SpeechRecognitionData.from_json(
  File "/home/louis/miniconda3/envs/w2vlf/lib/python3.8/site-packages/flash/core/data/data_module.py", line 1005, in from_json
    return cls.from_data_source(
  File "/home/louis/miniconda3/envs/w2vlf/lib/python3.8/site-packages/flash/core/data/data_module.py", line 571, in from_data_source
    train_dataset, val_dataset, test_dataset, predict_dataset = data_source.to_datasets(
  File "/home/louis/miniconda3/envs/w2vlf/lib/python3.8/site-packages/flash/core/data/data_source.py", line 307, in to_datasets
    train_dataset = self.generate_dataset(train_data, RunningStage.TRAINING)
  File "/home/louis/miniconda3/envs/w2vlf/lib/python3.8/site-packages/flash/core/data/data_source.py", line 344, in generate_dataset
    data = load_data(data, mock_dataset)
  File "/home/louis/miniconda3/envs/w2vlf/lib/python3.8/site-packages/flash/audio/speech_recognition/data.py", line 103, in load_data
    dataset_dict = load_dataset(self.filetype, data_files={stage: str(file)})
  File "/home/louis/miniconda3/envs/w2vlf/lib/python3.8/site-packages/datasets/load.py", line 1599, in load_dataset
    builder_instance = load_dataset_builder(
  File "/home/louis/miniconda3/envs/w2vlf/lib/python3.8/site-packages/datasets/load.py", line 1457, in load_dataset_builder
    builder_instance: DatasetBuilder = builder_cls(
  File "/home/louis/miniconda3/envs/w2vlf/lib/python3.8/site-packages/datasets/builder.py", line 285, in __init__
    with FileLock(lock_path):
  File "/home/louis/miniconda3/envs/w2vlf/lib/python3.8/site-packages/datasets/utils/filelock.py", line 323, in __enter__
    self.acquire()
  File "/home/louis/miniconda3/envs/w2vlf/lib/python3.8/site-packages/datasets/utils/filelock.py", line 272, in acquire
    self._acquire()
  File "/home/louis/miniconda3/envs/w2vlf/lib/python3.8/site-packages/datasets/utils/filelock.py", line 403, in _acquire
    fd = os.open(self._lock_file, open_mode)
OSError: [Errno 36] File name too long: '/home/louis/.cache/huggingface/datasets/_home_louis_.cache_huggingface_datasets_json_default-98e6813a547f72fa_0.0.0_c2d554c3377ea79c7664b93dc65d0803b45e3279000f993c7bfd18937fd7f426.lock'
```

My home directory is encrypted, therefore the maximum length is 143 ([source 1](https://github.com/ray-project/ray/issues/1463#issuecomment-425674521), [source 2](https://stackoverflow.com/a/6571568/2668831))

From what I've read I think the error is in reference to the file name (just the final part of the path) which is 145 chars long:

```py
>>> len("_home_louis_.cache_huggingface_datasets_json_default-98e6813a547f72fa_0.0.0_c2d554c3377ea79c7664b93dc65d0803b45e3279000f993c7bfd18937fd7f426.lock")
145
```

I also have a file in this directory (i.e. whose length is not a problem):

```py
>>> len("_home_louis_.cache_huggingface_datasets_librispeech_asr_clean_2.1.0_468ec03677f46a8714ac6b5b64dba02d246a228d92cbbad7f3dc190fa039eab1.lock")
137
```