refactor: pin system requirements to favor controlled updates

[mariajgrimaldi]

Description

This PR pins the runner system requirements (like Ubuntu version and Python) to specific versions to avoid errors when GH automatically updates its runner images. Also, before upgrading, we need to ensure all of our in-house tutor plugins support Python 3.12.

These changes were initially motivated by this error raised in recent runs of the workflow: https://github.com/eduNEXT/ednx-strains/actions/runs/11364833228/job/31611954196, which was caused by the ubuntu-latest image being updated to ubuntu-24.04 on Oct 6th.

See #30 (comment) for more details on the motivation for this PR.

[mariajgrimaldi]

For anyone joining the conversation:

The build service was temporarily unavailable because of the ubuntu-latest update from ubuntu-22.04 to ubuntu-24.04. Specifically, actions/runner-images#10781

The root cause of the problem is that the image being used for the ubuntu-24.04 runners is using the python interpreter which ships with the OS, which is externally managed

Which caused the error I mentioned in the cover letter: https://github.com/eduNEXT/ednx-strains/actions/runs/11364833228/job/31611954196

The upgrade has been temporarily rolled out from production while the GH runner-images team figures out how to fix it. This means we're currently running with Ubuntu-latest (Ubuntu-22.04).

Although the error was temporarily fixed, this opens a bigger conversation for the Picasso maintenance team. Should we pin environment-wide requirements like Ubuntu / Python to favor more controlled updates? I'd say pinning both is worth considering.

[magajh]

Much better, thanks

[magajh]

Thanks @mariajgrimaldi, LGTM