Update rook/ceph Docker tag to v1.12.0

This MR contains the following updates:

Package	Type	Update	Change
rook/ceph	ironbank-docker	minor	v1.11.9 -> v1.12.0
rook/ceph		minor	v1.11.9 -> v1.12.0
rook/ceph	stage	minor	v1.11.9 -> v1.12.0

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