Add Salt 2018.3 tests

Change-Id: I555ba6ca37a9052550a6c2568a757022876ccb35
diff --git a/.kitchen.yml b/.kitchen.yml
index 8783099..5eb8dcc 100644
--- a/.kitchen.yml
+++ b/.kitchen.yml
@@ -32,7 +32,7 @@
 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: