Improvements

Rook v1.7.4 is a patch release limited in scope and focusing on small feature additions and bug fixes to the Ceph operator.

• Add missing error type check to exec (#8751, @BlaineEXE)
• Raise minimum supported version of Ceph-CSI to v3.3.0 (#8803, @humblec)
• Set the Ceph v16.2.6 release as the default version (#8743, @leseb)
• Pass region to newS3agent() (#8766, @thotz)
• Remove unnecessary CephFS provisioner permission (#8739, @Madhu-1)
• Configurable csi provisioner replica count (#8801, @Madhu-1)
• Allow setting the default storageclass for a filesystem in the helm chart (#8771, @kubealex)
• Retry object health check if creation fails (#8708, @BlaineEXE)
• Use the admin socket for the mgr liveness probe (#8721, @jmolmo)
• Correct the CephFS mirroring documentation (#8732, @leseb)
• Reconcile OSD PDBs if allowed disruption is 0 (#8698, @sp98)
• Add peer spec migration to upgrade doc (#8435, @BlaineEXE)
• Fix lvm osd db device check (#8267, @lyind)
• Refactor documentation to simplify for the Ceph provider (#8693, @travisn)
• Emphasize unit tests in the development guide (#8685, @BlaineEXE)