Add Salt 2018.3 tests

Change-Id: Ib9508e92bf5113fdcdf7ec538b2b19c65f06da9b
diff --git a/.kitchen.yml b/.kitchen.yml
index dd865f7..d4af7dc 100644
--- a/.kitchen.yml
+++ b/.kitchen.yml
@@ -47,7 +47,7 @@
 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: