As a deployer, I want to specify the desired version of Quay to be managed which will be maintained independent of automatic Operator updates in order to control the stability of my registry service.

Acceptance criteria:

• desired version is specified in a central place for each Quay deployment
• a supported range of versions is advertised
• attempting to update to unsupported/unrecognized versions leads to an immediate error without any attempt to modify the existing deployment
• only updates are supported for y-streams

Open Questions:

• z-streams downgrades allowed?