seqeval metric does not work with a recent version of sklearn: classification_report() got an unexpected keyword argument 'output_dict'
Sorry, I was using an old version of sequeval
## Describe the bug
A clear and concise description of what the bug is.

## Steps to reproduce the bug
```python
from datasets import load_dataset, load_metric
seqeval = load_metric("seqeval")
seqeval.compute(predictions=[['A']], references=[['A']])
```

## Expected results
The function computes a dict with metrics

## Actual results
```
---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
<ipython-input-39-69a57f5cf06f> in <module>
      1 from datasets import load_dataset, load_metric
      2 seqeval = load_metric("seqeval")
----> 3 seqeval.compute(predictions=[['A']], references=[['A']])

~/p3/lib/python3.7/site-packages/datasets/metric.py in compute(self, *args, **kwargs)
    396             references = self.data["references"]
    397             with temp_seed(self.seed):
--> 398                 output = self._compute(predictions=predictions, references=references, **kwargs)
    399 
    400             if self.buf_writer is not None:

~/.cache/huggingface/modules/datasets_modules/metrics/seqeval/81eda1ff004361d4fa48754a446ec69bb7aa9cf4d14c7215f407d1475941c5ff/seqeval.py in _compute(self, predictions, references, suffix)
     95 
     96     def _compute(self, predictions, references, suffix=False):
---> 97         report = classification_report(y_true=references, y_pred=predictions, suffix=suffix, output_dict=True)
     98         report.pop("macro avg")
     99         report.pop("weighted avg")

TypeError: classification_report() got an unexpected keyword argument 'output_dict'
```

## Environment info
sklearn=0.24
datasets=1.1.3

