Switch to release-2.14 for all versions except 4.15

acm-2.14 is available on OCP: 4.1{6789}

For ocp-4.15 we use acm-2.13

Author: mbaldessari

overrides/values-4.18-hub.yaml renamed to overrides/values-4.15-hub.yaml

@@ -11,7 +11,7 @@ clusterGroup:
     acm:
       name: advanced-cluster-management
       namespace: open-cluster-management
-      channel: release-2.11
+      channel: release-2.14
       # csv: advanced-cluster-management.v2.6.1
   projects:
     - hub