[ci] Update loki-operator to stable-6.4 channel

Author: elfiesmelfie

ci/deploy-loki-for-ck.yaml

@@ -20,7 +20,7 @@ metadata:
   name: loki-operator
   namespace: openshift-operators-redhat
 spec:
-  channel: stable-6.3
+  channel: stable-6.4
   name: loki-operator
   source: redhat-operators
   sourceNamespace: openshift-marketplace