Bump CI image to use Chrome 71.0 and Golang 1.11

.gitlab-ci.yml

-image: "dev.gitlab.org:5005/gitlab/gitlab-build-images:ruby-2.5.3-golang-1.9-git-2.18-chrome-69.0-node-10.x-yarn-1.12-postgresql-9.6-graphicsmagick-1.3.29"
+image: "dev.gitlab.org:5005/gitlab/gitlab-build-images:ruby-2.5.3-golang-1.11-git-2.18-chrome-71.0-node-10.x-yarn-1.12-postgresql-9.6-graphicsmagick-1.3.29"
 
 .dedicated-runner: &dedicated-runner
   retry: 1
@@ -624,7 +624,7 @@ gitlab:setup-mysql:
 # Frontend-related jobs
 gitlab:assets:compile:
   <<: *dedicated-no-docs-pull-cache-job
-  image: dev.gitlab.org:5005/gitlab/gitlab-build-images:ruby-2.5.3-git-2.18-chrome-69.0-node-8.x-yarn-1.12-graphicsmagick-1.3.29-docker-18.06.1
+  image: dev.gitlab.org:5005/gitlab/gitlab-build-images:ruby-2.5.3-git-2.18-chrome-71.0-node-8.x-yarn-1.12-graphicsmagick-1.3.29-docker-18.06.1
   dependencies: []
   services:
     - docker:stable-dind