Release oslo.messaging 11.0.0

This version officially drop the python 2 support so we release a major
version of oslo.messaging to inform user that we break
the backward compatibility.

OpenStack is dropping the py2.7 support in ussuri cycle.

Complete discussion & schedule can be found in
-
http://lists.openstack.org/pipermail/openstack-discuss/2019-October/010142.html
- https://etherpad.openstack.org/p/drop-python2-support

Ussuri Communtiy-wide goal:
https://governance.openstack.org/tc/goals/selected/ussuri/drop-py27.html

Change-Id: If80225ad5c1153b6191c36178f8e8572189aa893

deliverables/ussuri/oslo.messaging.yaml

@@ -23,6 +23,10 @@ releases:
     projects:
       - repo: openstack/oslo.messaging
         hash: 41a44230434cf9037d57f5e26c1cc73559e198c7
+  - version: 11.0.0
+    projects:
+      - repo: openstack/oslo.messaging
+        hash: 32a1b6e94845b081e9c00d235320b2014cf18d71
 branches:
   - name: feature/nats-driver
     location: