Fix manifest aggregation

Signed-off-by: Federico Busetti <[email protected]>

Author: febus982

.gitlab_ci/_templates.yml

@@ -46,7 +46,8 @@ variables:
   script:
     - *docker-gitlab-login
     - echo "Building $DOCKER_IMAGE_FULL_TAG multiarch manifest"
-    - docker buildx imagetools create $DOCKER_IMAGE_FULL_TAG
+    - docker buildx imagetools create
+      --tag $DOCKER_IMAGE_FULL_TAG
       $DOCKER_IMAGE_FULL_TAG-linuxamd64
       $DOCKER_IMAGE_FULL_TAG-linuxarm64