Adding request for #flink-operator slack channel.

This channel request is for the Flink Operator project.

See: https://github.com/GoogleCloudPlatform/flink-on-k8s-operator

communication/slack-config/channels.yaml

@@ -66,6 +66,7 @@ channels:
   - name: falco
   - name: fiaas
   - name: fi-users
+  - name: flink-operator
   - name: fr-events
   - name: fr-users
   - name: garden