drop s390x, update ci

[braingram]

This PR removes the currently failing s390x workflow.
https://github.com/asdf-format/asdf/actions/runs/10245071412

On main this workflow tests 2 architectures

• arm64: the tests for this are passing on main but take 2.5 hours due to architecture emulation. This could more easily be covered by using the mac runners which this PR achieves.
• s390x: this is failing due an error building psutil. I am not sure why it's failing but I don't think it's worth trying to maintain a workflow for this rare architecture. If it's critical for distributions that package asdf (like debian) I believe they are more well-suited to testing with this architecture.

This PR includes a change updating the python version for a few CI jobs. The mac one was required as python 3.9 (the version on main) prevents use of macosx-latest: https://github.com/OpenAstronomy/github-actions-workflows/blob/924441154cf3053034c6513d5e06c69d262fb9a6/tools/tox_matrix.py#L139

The others are:

• drop python 3.9 from devdeps as many libraries are dropping python 3.9 support
• increase python version from 3.9 to 3.11 for compatibility and windows tests. These are unrelated but seem worth doing as python 3.9 is less common.

Checklist:

• pre-commit checks ran successfully
• tests ran successfully
• for a public change, a changelog entry was added
• for a public change, documentation was updated
• for any new features, unit tests were added