doc: Add CirrusCI status badge to README.
Badge for CirrusCI just like for other CI systems.
Acked-by: Aaron Conole
@@ -10,6 +10,8 @@ Open vSwitch
:target: https://travis-ci.org/openvswitch/ovs
.. image:: https://ci.appveyor.com/api/projects/status/github/openvswitch/ovs?branch=master&svg=true&retina=true
:target: https://ci.appveyor.com/project/blp/ovs/history
+.. image:: https://api.cirrus-ci.com/github/openvswitch/ovs.svg
+ :target: https://cirrus-ci.com/github/openvswitch/ovs
What is Open vSwitch?
---------------------
