hammer-cli-foreman has a release flow, but it's broken.

It's only triggered on tags with a v prefix: https://github.com/theforeman/hammer-cli-foreman/blob/d8b89dc7c7178c9203c7385778cc231e75e7617c/.github/workflows/release.yml#L7

In addition, it uses voxpupuli/ruby-release which internally uses gem build but Hammer is supposed to use rake build: https://github.com/theforeman/hammer-cli-foreman/blob/d8b89dc7c7178c9203c7385778cc231e75e7617c/.github/workflows/release.yml#L20

It documents the release process in rel-eng/README.md but we should track this in RELEASE.md and update where needed.