Update required Ansible version to be atleast 2.3

meta/main.yml

@@ -2,7 +2,7 @@ galaxy_info:
   author: Calum MacRae
   description: Deploy a full Sensu monitoring stack; including redis, RabbitMQ & the Uchiwa dashboard
   license: MIT
-  min_ansible_version: 2.0
+  min_ansible_version: 2.3
   platforms:
   - name: EL
     versions: