Add Salt 2018.3 tests

Change-Id: I936a5707dca965473446ce05da2f1872f9f6c443
diff --git a/.kitchen.yml b/.kitchen.yml
index f343e41..d4c9f5e 100644
--- a/.kitchen.yml
+++ b/.kitchen.yml
@@ -46,7 +46,7 @@
 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: