Update cluster logging operator (#1280)

Author: rajivnathan

setup/operators/installtemplates/cluster-logging-operator.yaml

@@ -15,7 +15,7 @@ objects:
     labels:
       operators.coreos.com/cluster-logging.openshift-logging: ""
   spec:
-    channel: stable-6.3
+    channel: stable-6.4
     installPlanApproval: Automatic
     name: cluster-logging
     source: redhat-operators