CI: Python 3.9 not on MacOS latest any more, but 3.12 also fails

[slobentanzer]

CI fails for the current 3.9-3.11 matrix, due to (https://github.com/biocypher/biocypher/actions/runs/8815890423)

The version '3.9' with architecture 'arm64' was not found for macOS 14.4.1.
The list of all available versions can be found here: https://raw.githubusercontent.com/actions/python-versions/main/versions-manifest.json

Tried moving to 3.10-3.12 in e38bf3b, but that fails also due to the MacOS runner (for 3.12, in https://github.com/biocypher/biocypher/actions/runs/8815934214/job/24198921052):

Detected M-series processor runner without nested virtualization support, exiting.
Error: Process completed with exit code 1.

Question is what to do in the CI setup:

• fix MacOS version that works with 3.9? (feels less useful, because we lose testing the newest MacOS)
• try to move up to 3.10-3.12? (I feel that 3.9 still is used quite a bit, so not too sure)
• some custom solution for now to get rid of the error? (skip 3.9 in MacOS latest?)

[nilskre]

Temporary workaround: Set macos to the last arm version as described here.

[nilskre]

Current solution: fix the macos runner version to macos-13.

The setup-python action is now fixed for macos-14 (at the moment this is macos-latest).
But the setup-docker-macos-action will only be updated for macos-15.