Release automaton 2.0.0

This version officially drop the python 2 support so we release a major
version of automaton 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: I18f2bcffdaa9d57d5287f1d28d7fce24d3320c3b

deliverables/ussuri/automaton.yaml

@@ -6,3 +6,8 @@ team: oslo
 type: library
 repository-settings:
   openstack/automaton: {}
+releases:
+  - version: 2.0.0
+    projects:
+      - repo: openstack/automaton
+        hash: 1161c1c60cc896b7f44942466e9edbce45368f6a