[CI] Introduce deprecated tasks checks

[eskultety]

Whenever a PR making repository-wide task updates one may accidentally introduce changes to tasks present in the archived-tasks directory. To prevent such accidental updates which can be painful depending on old decisions and precedents which are no longer applicable we should add a GH action check that looks at which files are being updated and fail if:

• changes to archived-tasks
• changes to tasks which are beyond their expires-on date, but haven't been deprecated (or moved to the archive for that matter) for some reason yet

Related to: #2509

[chmeliik]

What would be the purpose of this check? If it's to protect contributors from spending time on archived tasks, then a CI check would come too late.

[eskultety]

If it's to protect contributors from spending time on archived tasks, then a CI check would come too late.

That is true, yes, however, I meant it more like a supplementary thing. It's not just for contributors, but also for reviewers, i.e. it's easy to miss this fact. The way the CI is currently structured, there are a few "verify" scripts present in the repo that run as part of the CI checks as opposed to the generate scripts which are supposed to be called prior opening a PR, so that could also be one way of providing an early feedback ,because one can literally run those verify scripts locally and get a result in 3 seconds (and if changes aren't introduced in one huge lump but instead gradually it may even work). So, yes, we cannot prevent a wasted effort 100%, but we can at least mitigate the effect of it and provide means of both verifying as well as consistently conforming to an agreed set of deprecation rules in this case.

[Amanyd]

Hi @eskultety , I was looking into this and put together a draft implementation here, let me know if this aligns with how you want to handle deprecation checks moving forward