[SHIP-0038] Use Release Branches for Releasing

[adambkaplan]

Is there an existing feature request for this?

• [X] I have searched the existing feature requests

Is your feature request related to a problem or use-case? Please describe.

Per SHIP-0038, we are changing our release process to ship official releases from a release branch, rather than from main.

Describe the solution that you would like.

• CI and release scripts can be run on a release branch (with release-v* pattern)
• Release workflows must use an appropriate release branch and/or git reference (cannot blindly use latest commit from main)

Describe alternatives you have considered.

See SHIP-0038 for discussion

Anything else?

Part of https://github.com/shipwright-io/community/issues/85

[qu1queee]

@adambkaplan how long does this issue needs to be open? what is missing?

[adambkaplan]

I think we call this "Done" when we release v0.13.0 for the operator (or at least a candidate). This is currently blocked by #184 (which we made progress on today).