Pinned actions versions and add Dependabot configuration

[Zeitsperre]

Closes #61

Changes

• Pins Actions version to their respective commit hashes according to their versions
• Adds a Dependabot configuration to keep this commit hashes up-to-date (quarterly scheduled)
• Adds a Python 3.14 build to CI
• Updates and re-runs pre-commit hooks

Discussion

The action relies on pytest and more-itertools. These could also be pinned according to their hashes if we were to use pip-tools (and also updated automatically by Dependabot). I can quickly add this on if people would like.

[bsipocz]

Thank you!

Some minor comments for the config, otherwise it looks good.

[bsipocz]

Thanks!

[keewis]

I'd probably use uv run for this (in a new PR). Am I correct in assuming that what you're looking for is a lock file?

[Zeitsperre]

Yes, precisely. I'm not using uv yet, but that's what I had in mind using something like:

python -m pip install --require-hashes -r CI/requirements.txt

[keewis]

the only reason I used pip when writing this action is because that was the one I was most familiar with at the time. Considering that using uv would allow us to use a fully isolated env for this action and thus avoid clashing with the activated environment, I believe that would actually be a welcome side-effect.

[Zeitsperre]

Darn, it looks like the following is invalid:

update-types:
  - *

Better to simply drop that entry.