try to also push to gitlab registry

.github/workflows/build-images.yml

@@ -42,14 +42,21 @@ jobs:
           username: ${{ github.actor }}
           password: ${{ secrets.GITHUB_TOKEN }}
 
+      - uses: docker/login-action@v3
+        with:
+          registry: gitlab-registry.cern.ch
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITLAB_REGISTRY_PUSH_TOKEN }}
+
       - name: Docker meta
         id: meta
         uses: docker/metadata-action@v5
         with:
           # list of Docker images to use as base name for tags
           images: |
             ghcr.io/${{ github.repository_owner  }}/${{ matrix.context }}
-          # generate Docker tags based on the following events/attributes
+            gitlab-registry.cern.ch/acts/machines/${{ matrix.context }}
+          # generate Docker tags based on the following events/attributesk
           tags: |
             type=schedule
             type=ref,event=branch