build: switch to python 3.12

[afuetterer]

Description

Fixes #516

I don't know why the tests failed before, but there was at least one dependency blocking from moving to Python 3.12.

It seems to be working though. What do you think?

Types of changes

• Breaking change (fix or feature that would cause existing functionality to change)
• Build related changes

Checklist

• I have read the contributor guide.
• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have added tests to cover my changes.
• All new and existing tests passed.

[afuetterer]

If you choose to accept this, a new fuji version, and a note about switching python versions would be appropriate.

[afuetterer]

Maybe there should be a test that builds the docker image in ci and runs some command to verify building is possible.