Update Base Image To Build Tools CI 6.x (#129)

* Use `google-chrome` not `google-chrome-unstable`

* Use `6.x` release of `docker-build-tools-ci`

Author: ataylorme

.ci/scripts/03-test

@@ -32,7 +32,7 @@ set -ex
 
 # Start headless Chrome
 echo "\n Starting Chrome in headless mode ..."
-google-chrome-unstable --disable-gpu --headless --remote-debugging-address=0.0.0.0 --remote-debugging-port=9222 --no-sandbox </dev/null &>/dev/null &
+google-chrome --disable-gpu --headless --remote-debugging-address=0.0.0.0 --remote-debugging-port=9222 --no-sandbox </dev/null &>/dev/null &
 
 SELF_DIRNAME="`dirname -- "$0"`"
 $SELF_DIRNAME/run-behat

.circleci/config.yml

@@ -1,7 +1,7 @@
 # https://circleci.com/docs/2.0/workflows/#using-workspaces-to-share-data-among-jobs
 defaults: &defaults
   docker:
-    - image: quay.io/pantheon-public/build-tools-ci:5.x
+    - image: quay.io/pantheon-public/build-tools-ci:6.x
   working_directory: ~/example_wordpress_composer
   environment:
     #=========================================================================