Document the release process and fix the automated portions

[galargh]

Done Criteria

1. There is a RELEASE.md file that outlines the release process, even if it's just pointing at the automation.
2. The issues discovered during the v19.0.0 release (PR) are addressed

• The default GitHub token used by release.yml cannot push d3d71d3 to the default branch because the default branch requires changes to be made through pull requests
• It cannot create a tag either because git push is performed atomically by cargo release
• The release commit created by cargo release does not contain changelog changes (e.g. 0e64ce8)

Why Important

Reduce time to do a release or remembering/investigating how.

User/Customer

Maintainers

[BigLep]

2025-08-12 discussion between FilOz and IPDX: we proposed that will tackle these items the next time there is a release for this repo.

[BigLep]

@galargh : FYI that I expanded the scope of this issue to also include creating a RELEASE.md

[galargh]

That's a great point, thank you 🙏