Add Salt 2018.3 tests

Change-Id: Ie5d97134fb8c6b89633f99a3df670847b680c086
diff --git a/.kitchen.yml b/.kitchen.yml
index dc428ec..9c2a924 100644
--- a/.kitchen.yml
+++ b/.kitchen.yml
@@ -33,7 +33,7 @@
 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: