DRAFT: add an adhoc chart-releaser

[colearendt]

add an adhoc chart-releaser that is triggered by the /release-adhoc…

This allows for releasing (in an adhoc fashion) from a branch. Unfortunately the behavior and how this will work for non-devel releases is not super well-defined. If chart-releaser adds support for filtering to only certain releases, that would be helpful to make this safer: helm/chart-releaser#196

In particular, it is most concerning if chart A moves to --devel version on the dev branch, chart B moves to a newer version on main, and then CI runs based on a /release-adhoc comment. It would also be concerning if chart A or chart B move to a newer version on a branch and then publish a "non-devel" version from the branch.

It requires being an OWNER on the repository, although it is unclear if this correlates to ADMIN privileges within the organization.

[colearendt]

Moved this to a draft, because @atheriel and I decided that:

• this has some potentially annoying / dangerous edge cases (creating a mess that will be annoying to clean up)
• it is an attempt to solve a set of problems that could also be solved other ways... i.e.
  • A different release mechanism compared to chart-releaser (chart releaser creates some of these problems)
  • A different branching mechanism (i.e. running dev releases off of the dev branch) and merging back/forth from main to keep things up to date
  • Triggering off of tags and running tag-based releases
  • Using the main branch, but dev versions and having a more formal release process where the action is triggered manually when a release is desirable
• Ultimately the demand for this feature is relatively short-lived and rare (i.e. once every 3-6 months). It can usually be ameliorated in other ways (i.e. by being careful on main, blocking main for new point releases while a dev release is in flight, etc.).

Much of this pain is caused by having the version in Chart.yaml and README.md, the merge conflicts that that creates, and only having a single "source of truth" to trigger releases (i.e. main) - or again causing more merge conflicts.