fix

.gitlab-ci.yml

@@ -21,6 +21,7 @@ build:
                                --tag $IMAGE_NAME:latest 
                                --tag $IMAGE_NAME:${VERSION}-${UPSTREAM_RELEASE_TAG}
                                --tag $IMAGE_NAME:${VERSION}
+                               --build-arg UNBOUND_TAG=${UPSTREAM_RELEASE_TAG}
                                .
                 - docker login -u gitlab-ci-token -p $CI_JOB_TOKEN $CI_REGISTRY
                 - docker push $IMAGE_NAME:${CI_COMMIT_SHORT_SHA}