build(python): fix `docs` and `docfx` builds#581

parthea merged 3 commits intomaingoogleapis/python-api-core:mainfrom

owl-bot-update-lock-5ea6d0ab82c956b50962f91d94e206d3921537ae5fe1549ec5326381d8905cfagoogleapis/python-api-core:owl-bot-update-lock-5ea6d0ab82c956b50962f91d94e206d3921537ae5fe1549ec5326381d8905cfaCopy head branch name to clipboard