ICU-22946 Pin all -latest runners per ICU-TC 2024-10-17 🗡️

[eggrobin]

Pin ubuntu-latest, windows-latest, and macos-latest to their current values, with a note that those are updated in the BRS (I have added a post-release task to the BRS for that).

It does not seem trivial to have that configuration in a single place (configuration variables would work, but those are not part of the repository itself, so they are not source-controlled and they are only accessible to repository owners; I am also not sure how they would behave with PRs from forks). It might be possible to reduce this to one occurrence per file, but 22 files is enough that I would want to three global substitutes anyway, at which point it does not make a difference that there are 83 of them.

Checklist

• Required: Issue filed: https://unicode-org.atlassian.net/browse/ICU-22946
• Required: The PR title must be prefixed with a JIRA Issue number. Example: "ICU-1234 Fix xyz"
• Required: The PR description must include the link to the Jira Issue, for example by completing the URL in the first checklist item
• Required: Each commit message must be prefixed with a JIRA Issue number. Example: "ICU-1234 Fix xyz"
• Issue accepted (done by Technical Committee after discussion)
• Tests included, if applicable
• API docs and/or User Guide docs changed or added, if applicable

[markusicu]

I reopened @FrankYFTang 's ticket in order to unblock this PR.

[markusicu]

I am happy to rubber-stamp these changes, but we should also have documentation for the new BRS task.

I suggest adding a section here:

• https://unicode-org.github.io/icu/processes/release/tasks/build.html
• https://github.com/unicode-org/icu/blob/main/docs/processes/release/tasks/build.md

Maybe just before the obsolete "Update the pool bundles".

[jira-pull-request-webhook]

Notice: the branch changed across the force-push!

• docs/processes/release/tasks/build.md is now changed in the branch

View Diff Across Force-Push

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[markusicu]

tnx!

[mihnita]

Wow, that's a lot of files!

We should probably look into some cleanup...
(not now, of course)

Thank you for this one,
Mihai