GitHub Actions: Mechanism to deploy releases to PuppetForge/RubyGems.org, etc

This issue may need to be split in a separate issue per deployment target.

Some workflow decisions will need to be made before this goes into production. They probably all need to be tracked in their own issues:

• Intiatation:

  • A simple way initiate a release from GitHub is through the GitHub Releases process, which creates a tag. This is the opposite of our Travis CI pipeline deployments, which create a GitHub releases after a tag pipeline runs.

  • A more RELENG-specific method might be a manual event to trigger a RELENG-specific method that does both.

• RELENG process:

  • This would be a good point to implement deferred asset version bumps

    • This would allow CI to check for both SemVer correctness and RELENG requirements, without confusing the two

    • Which in turn would streamline normal development, as CI would no longer halt all important tests to insist on unnecessary/redundant version bumps before releases.

  • Decide how the pipeline should handle deployment failures, and how we would recover from them