Update the ARM64 CI AMI.

[benjyw]

This AMI will have all pythons from 3.7 to 3.13 preinstalled.

Also update the docs on how to create it.

[benjyw]

This will be cherrypicked to all active release branches so that we can reap the old AMIs sooner (RunsOn make no guarantees about continuing to work on older AMIs, so this sort of cherrypicking is going to be necessary from time to time).

[benjyw]

Hmm, will have to merge the label changes separately, since the new AMI only takes effect after merging, but the label changes take effect in this PR.

[WorkerPants]

I tried to automatically cherry-pick this change back to each relevant milestone, so that it is available in those older releases of Pants.

❌ 2.21.x

I was unable to cherry-pick this PR to 2.21.x, likely due to merge-conflicts.

Steps to Cherry-Pick locally

To resolve:

1. (Ensure your git working directory is clean)
2. Run the following script to reproduce the merge-conflicts:

   git fetch https://github.com/pantsbuild/pants main \
     && git fetch https://github.com/pantsbuild/pants 2.21.x \
     && git checkout -b cherry-pick-21531-to-2.21.x FETCH_HEAD \
     && git cherry-pick fe332667d1839962d4bdfa852d6bd68c6c98424f

3. Fix the merge conflicts and commit the changes
4. Run build-support/cherry_pick/make_pr.sh "21531" "2.21.x"

Please note that I cannot re-run CI if a job fails. Please work with your PR approver(s) to re-run CI if necessary.

❌ 2.22.x

I was unable to cherry-pick this PR to 2.22.x, likely due to merge-conflicts.

Steps to Cherry-Pick locally

To resolve:

1. (Ensure your git working directory is clean)
2. Run the following script to reproduce the merge-conflicts:

   git fetch https://github.com/pantsbuild/pants main \
     && git fetch https://github.com/pantsbuild/pants 2.22.x \
     && git checkout -b cherry-pick-21531-to-2.22.x FETCH_HEAD \
     && git cherry-pick fe332667d1839962d4bdfa852d6bd68c6c98424f

3. Fix the merge conflicts and commit the changes
4. Run build-support/cherry_pick/make_pr.sh "21531" "2.22.x"

Please note that I cannot re-run CI if a job fails. Please work with your PR approver(s) to re-run CI if necessary.

✔️ 2.23.x

Successfully opened #21533.

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When you're done manually cherry-picking, please remove the needs-cherrypick label on this PR.

Thanks again for your contributions!

🤖 Beep Boop here's my run link