Announce ansible-collections-openstack in openstack-ansible-sig

The ansible sig is going to be doing development on these modules,
so announce their patches into the channel.

Change-Id: Ifd6e4ef8a6b49928754ab75c20830ee07b62cfa9

gerritbot/channels.yaml

@@ -326,6 +326,16 @@ openstack-ansible:
     - ^stable/.*
     - master
 
+openstack-ansible-sig:
+  events:
+    - patchset-created
+    - change-merged
+  projects:
+    - openstack/ansible-collections-openstack
+  branches:
+    - ^stable/.*
+    - master
+
 openstack-architecture:
   events:
     - patchset-created