[BUG] Fix broken link in the README for entailment examples.

[Narayan Acharya]

Description

The link for the Multi NLI dataset entailment example for a local setup is broken in the README.

How do we replicate the bug?

Click the link for 'entailment_multinli_bert.ipynb' in the README at the end.
Link redirects to a 404 GitHub page.

Expected behavior (i.e. solution)

Clicking on the example notebook link should open the example python notebook file name 'entailment_multinli_transformers.ipynb' in the same directory instead of redirecting to a 404.

Other Comments

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