Review ownership/licensing of the project

[gpocentek]

My name is everywhere in the code, we need to update information to make the project belong to the python-gitlab team.

Things to do:

• [ ] update gitlab/__init__.py (__author__, __email__, __copyright__)
• [ ] review the files headers for copyright update

[max-wittig]

@bufferoverflow What do you think? I would just close it. From my point of view, it's totally fine if @gpocentek is in the copyrights. He is the original creator.

[bufferoverflow]

I'm unsure how author is handled and if there is e.g. a maintainer field within setup.py.

https://pypi.org/project/python-gitlab/ shows the maintainers based on pypi access, maybe we can sync that with the content of setup.py