We're missing release notes about a change in shortname enforcement that came in 4.21. The following change needs to be added to 4.21 release notes as it could cause some pods to fail to start after upgrading to 4.21.

https://github.com/cri-o/cri-o/pull/9401

This could possibly be treated as something that requires deprecation and removal, if so then we should revert it in 4.21, add release notes saying it's deprecated and then enforce it again in 4.22.