drop 3.8 support, add 3.11

[alessandrofelder]

Description

What is this PR

• [ ] Bug fix
• [ ] Addition of a new feature
• [x] Other

Why is this PR needed?

We'd like to move to supporting python 3.11.

What does this PR do?

Drops Python 3.8 and adds 3.11 instead in pyproject.toml and GH actions workflow.

References

Closes #38

How has this PR been tested?

Checks in CI and locally on my Silicon Mac.

Is this a breaking change?

If you're using 3.8, yes.

Does this PR require an update to the documentation?

It's already documented that we follow NEP 29, so no.

Checklist:

• [x] The code has been tested locally
• [x] Tests have been added to cover all new functionality
• [x] The documentation has been updated to reflect any changes
• [x] The code has been formatted with pre-commit

[adamltyson]

@alessandrofelder I don't think this has changed the cookiecutter template itself.

[alessandrofelder]

Yep @adamltyson I just noticed too - I'll fix now.