Add stack_action_timeout parameter

Change-Id: Ia00e7e8868128119de3fb2a55775fbbc99bb5022
diff --git a/README.rst b/README.rst
index 7df62e0..bb543ff 100644
--- a/README.rst
+++ b/README.rst
@@ -68,6 +68,7 @@
           ha_queues: True
         max_stacks_per_tenant: 150
         max_nested_stack_depth: 10
+        stack_action_timeout: 7200
 
 Define server clients Keystone parameter: