Update special-casing of feature/buster
wiki/src/contribute/release_process.mdwn. In most places, s/buster/bullseye/ should be fine.
Special-case feature/bullseye instead of feature/buster (refs: #16945).
feature/buster is not a thing anymore.
- Status changed from In Progress to Needs Validation
- Assignee changed from intrigeri to anonym