Run dev workflow for external contributor PRs

[ggetz]

Description

I noticed that #11678 and other external PRs do not have any GitHub Action workflows run. Nor do I see the approval workflow as described in Approving workflow runs from public forks.

While its not very clear from the GitHub actions documentation, it appears that the external contributor workflows are expected to be triggered from PRs rather than pushes.

This PR also cleans up some missed references when transitioning from Node 16 and 18 to Node 18 and 20 to reflect LTS status.

Issue number and link

N/A

Testing plan

This should:

1. Trigger the dev workflow for this PR once opened
2. Once merged into main, newly opened external PRs and their updates should trigger the dev workflow.

Author checklist

• I have submitted a Contributor License Agreement
• I have added my name to CONTRIBUTORS.md
• I have updated CHANGES.md with a short summary of my change N/A
• I have added or updated unit tests to ensure consistant code coverage N/A
• I have update the inline documentation, and included code examples where relevant N/A
• I have performed a self-review of my code

[ggetz]

After speaking offline with @jjspace, we agreed on avoiding the double runs on PR updates where possible.

To avoid the double runs, we're going to run the deployment only for pushes (as these cannot be run by external contributors anyway), expect for those to the main or production branches. The the rest of the dev workflow will run on the pull_request trigger.

Ex.

on:
  push:
    branches:
      - main
      - production
      - "cesium.com"
  pull_request:

[ggetz]

@jjspace Updated!

[ggetz]

@jjspace Please review when you get the chance.

[jjspace]

Just had a couple questions

[ggetz]

@jjspace I answered your questions above. Is this OK to merge?

[jjspace]

@ggetz Yes, I was looking in the wrong part of the docs. LGTM 🙏