Backport #11213: gitlab ci: Use today's ci-images build; move to alpine3_22

[mergify]

• Background: Release CI has been implemented on GitHub, but my working assumption is that the previous GitLab CI will still be used for minor releases of 3.16 to ensure no breaking changes regarding platform availability.

• Situation: GitLab CI (may it soon RIP) is failing and will take a hot minute to fix again

  • An eager reaping process removed all the Docker images used by CI (I think? Ben Gamari may know).
  • The images can't be regenerated from the same commit, because apt-get update fails during the run.
  • The easiest workaround—using the latest commit—would force a change in platforms, albeit not much of one.

• Possible solutions

  • Option 1: Declare GitLab bankruptcy and give up. Go whole-hog on the new GitHub CI, platform availability be damned.

  • Option 2: Accept some minor change in platform availability. The list would be:

    • i386-alpine3_20 replaced by i386-alpine3_22
    • x86_64-alpine3_20 replaced by x86_64-alpine3_22
    • aarch64-alpine3_18 replaced by aarch64-alpine3_22

    Pipeline example:

  • Option 3: Something else that I realistically don't have time for and probably nobody else does, either.

This PR implements option 2. If merged, it should be backported to the 3.16 branch.

---

This is an automatic backport of pull request #11213 done by Mergify.

[mergify]

Merge Queue Status

🚫 The pull request has left the queue (rule: default)

This pull request spent 1 hour 40 minutes 2 seconds in the queue, including 1 hour 29 minutes 28 seconds running CI.
The checks were run on draft #11324.

Required conditions to merge

• any of [🛡 GitHub branch protection]:
  • check-neutral = Validate post job
  • check-skipped = Validate post job
  • check-success = Validate post job
• #approved-reviews-by >= 1 [🛡 GitHub branch protection]
  • Backport #11213: gitlab ci: Use today's ci-images build; move to alpine3_22 #11320
• #changes-requested-reviews-by = 0 [🛡 GitHub branch protection]
  • Backport #11213: gitlab ci: Use today's ci-images build; move to alpine3_22 #11320
• #review-threads-unresolved = 0 [🛡 GitHub branch protection]
  • Backport #11213: gitlab ci: Use today's ci-images build; move to alpine3_22 #11320
• any of [🛡 GitHub branch protection]:
  • check-success = Doctest Cabal
  • check-neutral = Doctest Cabal
  • check-skipped = Doctest Cabal
• any of [🛡 GitHub branch protection]:
  • check-success = Meta checks
  • check-neutral = Meta checks
  • check-skipped = Meta checks
• any of [🛡 GitHub branch protection]:
  • check-success = docs/readthedocs.org:cabal
  • check-neutral = docs/readthedocs.org:cabal
  • check-skipped = docs/readthedocs.org:cabal
• any of [🛡 GitHub branch protection]:
  • check-success = Bootstrap post job
  • check-neutral = Bootstrap post job
  • check-skipped = Bootstrap post job
• any of [🛡 GitHub branch protection]:
  • check-success = whitespace
  • check-neutral = whitespace
  • check-skipped = whitespace

Reason

The merge conditions cannot be satisfied due to failing checks

Failing checks:

• ❌ Validate post job

Hint

You may have to fix your CI before adding the pull request to the queue again.
If you update this pull request, to fix the CI, it will automatically be requeued once the queue conditions match again.
If you think this was a flaky issue instead, you can requeue the pull request, without updating it, by posting a @mergifyio requeue comment.