Add Salt 2018.3 tests

Change-Id: I6580beeb51870443eb1e72d581e215329c3db48f
diff --git a/.kitchen.yml b/.kitchen.yml
index 60bc140..22dc4e7 100644
--- a/.kitchen.yml
+++ b/.kitchen.yml
@@ -48,7 +48,7 @@
 platforms:
   - name: <%=ENV['PLATFORM'] || 'saltstack-ubuntu-xenial-salt-stable'%>
     driver_config:
-      image: <%=ENV['PLATFORM'] || 'epcim/salt-formulas:saltstack-ubuntu-xenial-salt-stable'%>
+      image: <%=ENV['PLATFORM'] || 'epcim/salt:saltstack-ubuntu-xenial-salt-stable'%>
       platform: ubuntu
 
 suites: