add verify step

.gitlab-ci.yml

@@ -7,6 +7,7 @@ stages:
   - buildAndTest
   - trigger
   - pages
+  - verify
 
 before_script:
   - yarn global add npmci
@@ -66,3 +67,12 @@ pages:
     expire_in: 1 week
     paths:
     - public
+
+verify:
+  stage: trigger
+  script:
+    - npmci docker pull registry.gitlab.com test
+  only:
+    - tags
+  tags:
+    - docker