Document Release cut CI requirements in hypershift repo

This is a placeholder to capture the necessary CI changes to do every release cut.

There are a few places in our CI config which requires pinning to the new release every release cut:

• Step registry / CLI https://github.com/openshift/release/pull/30297/files
• Mirroring images for both CPO and HO https://github.com/openshift/release/pull/30215
• Conformance jobs https://github.com/openshift/release/pull/29972
• Supported versions https://github.com/openshift/hypershift/pull/1575/files#diff-63fe5b9f7f4d0e344d2dfbf49aac7b3b9b46299371061221e5ff55d4a58f7db9R13

DOD:

Make sure we have this documented in hypershift repo and that all needed is done for current release branch.