As of Octopus, Ceph will prevent you from creating a pool with a
replica size of 1. Allowing such pool could lead to data loss, so enable
the new option: requireSafeReplicaSize: false if you are **ABSOLUTELY**
certain that is what you want.
Closes: https://github.com/rook/rook/issues/4889
Signed-off-by: Sébastien Han <seb@redhat.com>