Merge pull request #7566 from mnasiadka/slack/openstack-magnum

chore: add openstack-magnum channel

Author: k8s-ci-robot

communication/slack-config/channels.yaml

@@ -381,6 +381,7 @@ channels:
   - name: openshift-users
   - name: openstack-helm
   - name: openstack-kolla
+  - name: openstack-magnum
   - name: operator-builder
   - name: operator-framework-community
   - name: operator-sdk-dev