Update Docker version in gitlab:assets:compile

.gitlab/ci/frontend.gitlab-ci.yml

@@ -13,7 +13,7 @@
     - .default-before_script
     - .assets-compile-cache
     - .only:changes-code-backstage-qa
-  image: registry.gitlab.com/gitlab-org/gitlab-build-images:ruby-2.6.3-git-2.22-chrome-73.0-node-12.x-yarn-1.16-graphicsmagick-1.3.33-docker-18.06.1
+  image: registry.gitlab.com/gitlab-org/gitlab-build-images:ruby-2.6.3-git-2.22-chrome-73.0-node-12.x-yarn-1.16-graphicsmagick-1.3.33-docker-19.03.1
   stage: test
   dependencies: ["setup-test-env"]
   needs: ["setup-test-env"]