Try to login in registry first

.gitea/workflows/image.yaml

@@ -8,6 +8,12 @@ jobs:
     if: gitea.ref == 'refs/heads/main'
     steps:
       - uses: actions/checkout@v4
+      - name: Log in to Registry
+        uses: docker/login-action@v3
+        with:
+          registry: registry.brunner.ninja
+          username: ${{ secrets.REGISTRY_USERNAME }}
+          password: ${{ secrets.REGISTRY_PASSWORD }}
       - name: Set up Docker Buildx
         uses: docker/setup-buildx-action@v3
         with: