Upgrade GitHub Actions

[cclauss]

• https://github.com/actions/checkout/releases
• https://github.com/actions/setup-python/releases
• https://docs.python.org/3.12/whatsnew/3.12.html

Fix a flake8 error and move safety to a separate GitHub Action so we do not ignore Python test errors.

[MarcelCoding]

LGTM!

Changing the default branch would be helpful, that Dependabot would start working. Dependabot only checks the default branch for the default branch.

The configuration is already existing:
https://github.com/motioneye-project/motioneye/blob/dev/.github/dependabot.yaml

[MichaIng]

Would be good to check whether newly added tests are green before merging them 😉.

@cclauss
If I am no mistaken, safety checks all Python packages installed locally and globally on the system, and the GitHub runners come with a lot of which are not needed for motionEye, especially where we do not enforce any max version.

I think the test how it is currently added does not make any sense. It tests only the default GitHub runner Python environment, which has nothing to do with motionEye. We'd need to install motionEye, at best into a venv, to not test the GitHub runner, but what we really do install for motionEye?