Upgrade the `merge-trunk-develop-pr`, `prepare-extension-release`, and `publish-extension-dev-build` actions to use Node.js v20

[eason9487]

Changes proposed in this Pull Request:

Part of #108

This PR upgrades the merge-trunk-develop-pr, prepare-extension-release, and publish-extension-dev-build actions to use Node.js v20.

📌 Checklist before merging (@eason9487)

• [x] Revert 3f7ee00d93ac661ee0bd3f1cbd72316f4ff8333b before merging this PR

Detailed test instructions:

prepare-extension-release action

1. View a previous workflow run used v1 action
   • https://github.com/woocommerce/google-listings-and-ads/actions/runs/8794326378
   • There are warnings of using Node.js 16
2. View a test workflow run used updated action
   • https://github.com/eason9487/grow/actions/runs/8830586225
   • There's no more warning of using Node.js 16
3. View the new release PR created by this action
   • https://github.com/eason9487/grow/pull/18

merge-trunk-develop-pr action

1. View a previous workflow run used v1 action
   • https://github.com/woocommerce/google-listings-and-ads/actions/runs/8794629482
   • There are warnings of using Node.js 16
2. View a test workflow run used updated action
   • https://github.com/eason9487/grow/actions/runs/8830610829
   • There's no more warning of using Node.js 16
3. View the merging back PR created by this action
   • https://github.com/eason9487/grow/pull/19

publish-extension-dev-build action

1. View a previous workflow run used v1 action
   • https://github.com/woocommerce/google-listings-and-ads/actions/runs/8796669445
   • There are warnings of using Node.js 16 (woocommerce/grow/get-release-notes@actions-v1 andactions/github-script@v6`)
2. View a test workflow run used updated action
   • https://github.com/eason9487/grow/actions/runs/8830553471
   • There's no more warning of using Node.js 16
3. View the dev build published by this action
   • https://github.com/eason9487/grow/releases/tag/test-gha-dev-build

[eason9487]

Thanks for the review, @mikkamp

I was just curious about us running on ubuntu-latest. Release date of 24.04 is today, doesn't look like it's changed yet, but do we expect that to switch over without issues?

I think this is the expected way - these actions are continuously compatible with the ubuntu-latest in GitHub Actions Runner. Most of the actions depend on Node.js, PHP or the common CLI, so as long as these dependencies are consistently compatible with ubuntu-latest, there should be no problems.

I guess we can handle that separately if something does go wrong.

Yes, a few actions depend on more particular CLI, such as jq, or services that are more prone to major changes, such as MySQL. I suppose we could just deal with it when it happens.