Currently, revisions in an "Unknown" state don't have a pruning limit, so they can pile up forever. The revision pruner controller should be able to set a limit for these, similar to how it does for Succeeded and Failed revisions.

See https://bugzilla.redhat.com/show_bug.cgi?id=1801437

Open PRs:

1. https://github.com/openshift/api/pull/643 - API change to add the field
2. https://github.com/openshift/library-go/pull/794 - to implement the limit in the pruning controller