Update GitHub Action to github-script@v8 #33634

Version v8 introduces performance improvements, enhanced JavaScript runtime support, and updated dependencies for greater security and reliability. Release notes: actions/github-script@v8: https://github.com/actions/github-script/releases/tag/v8

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For details see: https://corecheck.dev/bitcoin/bitcoin/pulls/33634.

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cc @willcl-ark

Not sure there is any need to bump this myself. I think we should probably adopt a ~ policy to only bump when:

• a version is nearing End of Life
• we want a new feature from a new version
• other unknown reason arises

Its hard to say whether "randomly bumping to new versions" is more or less likely to cause issues than sticking around on older versions, and if we need to update eventually then perhaps the difference is exactly nothing. But I don't see a compelling reason to do this now.

Closing for now.

policy

I think the policy is "Ensure your workflows use the latest versions of actions that are running on Node 20. For more information, see Using Versions for Actions.". Source: https://github.blog/changelog/2023-09-22-github-actions-transitioning-from-node-16-to-node-20/#for-actions-users

Something similar may happen with node-24. However, I am not familiar with GHA, JavaScript, or Node, or npm, so I can't evaluate if any of this applies here.