Add Salt 2018.3 tests

Change-Id: I699d58f268ef3dd7471ecf74ed01def35089d7fc
diff --git a/.kitchen.yml b/.kitchen.yml
index 2c7c727..6ed2dda 100644
--- a/.kitchen.yml
+++ b/.kitchen.yml
@@ -30,7 +30,7 @@
 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
 
 verifier: