Add pyarrow-hotfix to release docs (#6421)

Add pyarrow-hotfix in release docs

Author: albertvillanova

setup.py

@@ -62,7 +62,7 @@
      ```
    Check that you can install it in a virtualenv/notebook by running:
      ```
-     pip install huggingface_hub fsspec aiohttp
+     pip install huggingface_hub fsspec aiohttp pyarrow-hotfix
      pip install -U tqdm
      pip install -i https://testpypi.python.org/pypi datasets
      ```