Update dependency to Ansible >=2.3.0

Author: ganto

README.md

@@ -20,7 +20,7 @@ This role installs and manages [Check_MK](http://mathias-kettner.com/check_mk.ht
 
 ### Installation
 
-This role requires at least Ansible `v2.1.5`. To install it, run:
+This role requires at least Ansible `v2.3.0`. To install it, run:
 
 ```Shell
 ansible-galaxy install debops-contrib.checkmk_server

meta/main.yml

@@ -11,14 +11,21 @@ galaxy_info:
   author: Reto Gantenbein
   description: 'Setup Check_MK monitoring server'
   license: 'GPL-3.0'
-  min_ansible_version: '2.1.5'
+  min_ansible_version: '2.3.0'
 
   platforms:
 
     - name: Debian
       versions:
         - wheezy
         - jessie
+        - stretch
+    - name: Ubuntu
+      versions:
+        - trusty
+        - xenial
+        - yakkety
+        - zesty
 
   galaxy_tags:
     - debops