Add Salt 2018.3 tests

Change-Id: Id18535354b1d99cea9536cf7506fa400722da977
diff --git a/.kitchen.yml b/.kitchen.yml
index 85b1fde..5cd20a4 100644
--- a/.kitchen.yml
+++ b/.kitchen.yml
@@ -40,7 +40,7 @@
 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: