[ci] change registry path to more stable name

.gitlab-ci.yml

@@ -11,7 +11,7 @@ stages:
     - whitewhale
   # Only build packages for https://0xacab.org/leap/bitmask-dev, not
   # for forks
-  image: "0xacab.org:4567/leap/gitlab-buildpackage:build_${DIST}_${ARCH}"
+  image: "registry.0xacab.org/leap/gitlab-buildpackage:build_${DIST}_${ARCH}"
   script:
     - "pwd; git describe"
     - git checkout incoming