Remove py37, add py311, and fix Rectangle kwarg error

[adrien-berchet]

I suggest you bump matplotlib>=3.6 in setup.py

EDIT: Ah no, nvm :smile:

[codecov-commenter]

Codecov Report

Merging #1082 (9783ee7) into master (20bddc5) will not change coverage. The diff coverage is n/a.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #1082 +/- ## ========================================= Coverage 100.00% 100.00% ========================================= Files 36 36 Lines 2452 2452 ========================================= Hits 2452 2452 ```

[eleftherioszisis]

Oh wait, we should also change the Python version in setup.py

Done.

[adrien-berchet]

I also found old Py versions in doc/source/developer.rst, should we update it too?

[adrien-berchet]

LGTM, thanks!