TST: list known registry tags and grep for current tag

.gitlab-ci.yml

@@ -123,6 +123,10 @@ test:
             CAOSDB_TAG=dev-latest;
         fi
       - echo $CAOSDB_TAG
+      - KNOWN_TAGS=$(curl -u testuser:$CI_REGISTRY_PASSWORD -X GET https://$CI_REGISTRY:5000/v2/caosdb/tags/list)
+      - echo $KNOWN_TAGS
+        # test if the caosdb registry knows our current tag
+      - echo $KNOWN_TAGS | grep "$CAOSDB_TAG"
       - docker login -u testuser -p $CI_REGISTRY_PASSWORD $CI_REGISTRY
       - docker pull $CI_REGISTRY_IMAGE:latest
       - cd .docker