Update .gitlab-ci.yml

.gitlab-ci.yml

+image: docker:19.03
+
+variables:
+  DOCKER_TLS_CERTDIR: "/certs"
+  DOCKER_DRIVER: overlay2
+
+services:
+  - docker:19.03-dind
+
+before_script:
+  - docker info
+
 test_build_image:
-  image: docker:git
   tags:
-  - docker
+  - dunitrust
   services:
   - docker:dind
   script:
@@ -10,9 +21,8 @@ test_build_image:
     - tags
 
 build_image:
-  image: docker:git
   tags:
-  - docker
+  - dunitrust
   services:
   - docker:dind
   script: