Test against Python 3.11, windows and update github actions.

[krisfremen]

At first I just wanted to get Python 3.11 to be tested, but I saw some TODO items and warnings in the github actions, so a few changes in this PR:

• Added Python 3.11
• Pinned Python 3.6 to ubuntu20.04
• Added Windows
• Updated versions of github actions

Cheers!

[karlicoss]

thank you!