ci: update mergify rules for v3.0
ci: update mergify rules for v3.0

updated mergify rules for auto backport
and merging for release-v3.0 branch.
Signed-off-by: Madhu Rajanna <60fbf37a92c2a0908e31296d18dadbec5a4dae17@gmail.com>

ceph/ceph-csi,ceph/ceph-csi,ceph/ceph-csi,ceph/ceph-csi