Add a python gitignore

[karan]

No description provided.

[bvandermoon]

Did you seen an issue with these files when submitting code to tpu-recipes? I don't remember seeing any files that needed to be ignored

[karan]

@bvandermoon I use pyenv which saves a .python-version file, which got me thinking that adding a Python gitignore would be a good idea.

[wdhongtw]

Maybe user-global ignore is a good choice here? Since that this repo does not provides any installable python module/package, most user probably will not setup a dedicate env for this repo.

https://docs.github.com/en/get-started/git-basics/ignoring-files#configuring-ignored-files-for-all-repositories-on-your-computer