Update parameter_server_training.ipynb

[v1incent]

Move "model.compile" under strategy scope.

[github-actions]

Preview

Preview and run these notebook edits with Google Colab:

• site/en/tutorials/distribute/parameter_server_training.ipynb

Rendered notebook diffs available on ReviewNB.com.

Format and style

Use the TensorFlow docs notebook tools to format for consistent source diffs and lint for style:

$ python3 -m pip install -U --user git+https://github.com/tensorflow/docs

$ python3 -m tensorflow_docs.tools.nbfmt notebook.ipynb

$ python3 -m tensorflow_docs.tools.nblint --arg=repo:tensorflow/docs notebook.ipynb

If commits are added to the pull request, synchronize your local branch: git pull origin patch-2

[rchao]

Thank you for the PR. Looks good to me.

[8bitmp3]

Thanks @v1incent @rchao