Add Salt 2018.3 tests

Change-Id: I9326d024809990b87482f08e2be93145cdeb8af1
diff --git a/.kitchen.yml b/.kitchen.yml
index 96ea71d..9b48880 100644
--- a/.kitchen.yml
+++ b/.kitchen.yml
@@ -45,7 +45,7 @@
 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: