Consider updating actions/checkout@v3 to v4

Might need to test out workflows first.

Github is forcing all actions to use Node20 by default. checkout v3 uses Node16: https://github.com/actions/checkout/releases/tag/v3.0.0
Seems like there is stable release, and you can also use versioned actions. Maybe we can configure dependabot to check this for us too if we want to keep update to minor versions at least?

https://docs.github.com/en/actions/writing-workflows/workflow-syntax-for-github-actions#example-using-versioned-actions

https://github.blog/changelog/2024-03-07-github-actions-all-actions-will-run-on-node20-instead-of-node16-by-default/

Start by inspecting the repository's GitHub Actions workflow files and identify every use of actions/checkout@v3. Test the workflows before and after the update; done means checkout uses the stable v4 release and the workflows run successfully under Node 20.

Written by the indexing model from the issue text.