switch back to trusty and install dpkg

Author: artlowel

.travis.yml

@@ -1,5 +1,5 @@
 sudo: required
-dist: xenial
+dist: trusty
 
 env:
   # Install the latest docker-compose version for ci testing.
@@ -37,6 +37,7 @@ addons:
     sources:
       - google-chrome
     packages:
+      - dpkg
       - google-chrome-stable
 
 language: node_js