Set up access for #openinfra channel

The Open Infrastructure Foundation is going to work on consolidating
its IRC channel names under a common namespace, #openinfra on
Freenode. Access has been granted to our bot account by the original
channel operators.

Change-Id: If407e4c4fa9d81c13577bac6240e02472a7fb6b2

accessbot/channels.yaml

@@ -132,6 +132,7 @@ channels:
   - name: oooq
   - name: opendev
   - name: opendev-meeting
+  - name: openinfra
   - name: openinfralabs
   - name: openinfralabs-monitoring
   - name: openstack