Update release CI scripts (boot compiler and platform support)

[mpickering]

release: Bump boot compiler for release to 9.10.2

Also bumps the cabal-install used during the release process to
3.14.2.0.



Update platforms for release jobs

* Drop deb9, ubuntu18 and centos7 jobs which are all EOL
* Add ubuntu24_04
* Build a very old alpine bindist (3.12) and a new one (3.20)
* Only build 3_20 bindist for alpine i386.

The list of release platforms after this commit is

Linux

* x86_64
  - deb10
  - deb11
  - deb12
  - fedora33
  - fedora36
  - fedora38
  - rocky8
  - ubuntu20_04
  - ubuntu22_04
  - ubuntu24_04
  - alpine3_12
  - alpine3_20
* i386
  - deb10
  - alpine3_20
* aarch64
  - deb10
  - deb11
  - deb12
  - alpine3_18

Darwin
* x86_64
* aarch64

Windows
* x86_64

---

Template B: This PR does not modify behaviour or interface

E.g. the PR only touches documentation or tests, does refactorings, etc.

Include the following checklist in your PR:

• Patches conform to the coding conventions.
• Is this a PR that fixes CI? If so, it will need to be backported to older cabal release branches (ask maintainers for directions).

[mpickering]

Here is a test gitlab pipeline: https://gitlab.haskell.org/haskell/cabal/-/pipelines/112082

[geekosaur]

Expediting this for 3.16 probably makes sense.

[ulysses4ever]

Right

[chreekat]

In the past, the GitLab CI has used the "wrong" GHC, so adding some checks is good. I just have some inline comments about how they work.

Marking as "approved" because I don't think any changes would need a re-review from me.

[chreekat]

I still don't grok the Cabal PR workflow, does somebody who does want to take the next step? 😁