Add Salt 2018.3 tests

Change-Id: Ib663614f2d0647ecdf1cb8e6c369dec6b5901480
diff --git a/.kitchen.yml b/.kitchen.yml
index bcbff46..2391d83 100644
--- a/.kitchen.yml
+++ b/.kitchen.yml
@@ -44,7 +44,7 @@
 platforms:
   - name: <%= ENV['PLATFORM'] || 'ubuntu-xenial' %>
     driver_config:
-      image: <%= ENV['PLATFORM'] || 'epcim/salt-formulas:saltstack-ubuntu-xenial-salt-2016.3' %>
+      image: <%= ENV['PLATFORM'] || 'epcim/salt:saltstack-ubuntu-xenial-salt-2016.3' %>
       platform: ubuntu
 
 suites: