When I am considering using a new Python library, perhaps the most important information I need is to be able to tell what versions of Python the library supports.

Typically I look for:

1. I look for PyPi badges at the top of the README.MD file. (for an example, see pyhocon)
2. A list of supported version in the README.MD more generally.
3. Version categories from the setup.py displayed in the PyPi page. (for an example, see pyhocon)

python-gitlab doesn't seem to have documentation describing this.

If you came up with a list, I would be willing to do the legwork to create a PR for this documentation fix.

(I realize that it mentions it in the docs, but I might not even make it there if it's not clear.)