Librarian Bot: Add base_model information to model

This pull request aims to enrich the metadata of your model by adding [`bert-base-cased`](https://huggingface.co/bert-base-cased) as a `base_model` field, situated in the `YAML` block of your model's `README.md`.

How did we find this information? We performed a regular expression match on your `README.md` file to determine the connection.

**Why add this?** Enhancing your model's metadata in this way:
- **Boosts Discoverability** - It becomes straightforward to trace the relationships between various models on the Hugging Face Hub.
- **Highlights Impact** - It showcases the contributions and influences different models have within the community.

For a hands-on example of how such metadata can play a pivotal role in mapping model connections, take a look at [librarian-bots/base_model_explorer](https://huggingface.co/spaces/librarian-bots/base_model_explorer).

This PR was requested via the [Librarian Bot](https://huggingface.co/librarian-bot) [metadata request service](https://huggingface.co/spaces/librarian-bots/metadata_request_service) by request of [davanstrien](https://huggingface.co/davanstrien)

README.md

@@ -1,21 +1,22 @@
 ---
+language:
+- en
 license: apache-2.0
+library_name: transformers
 tags:
 - generated_from_keras_callback
 - named entity recognition
 - bert-base finetuned
 - umair akram
-model-index:
-- name: MUmairAB/bert-ner
-  results: []
 datasets:
 - conll2003
-language:
-- en
 metrics:
 - seqeval
-library_name: transformers
 pipeline_tag: token-classification
+base_model: bert-base-cased
+model-index:
+- name: MUmairAB/bert-ner
+  results: []
 ---