use self hosted image for build

.gitea/workflows/ci.yml

@@ -95,7 +95,7 @@ jobs:
             echo "IMAGE_TAGS=branch-$SLUG" >> "$GITHUB_ENV"
           fi
       - name: Set up QEMU for cross-platform builds
-        run: docker run --rm --privileged tonistiigi/binfmt --install all
+        run: docker run --rm --privileged gitea.siegeln.net/cameleer/binfmt:1 --install all
       - name: Build and push server
         run: |
           docker buildx create --use --name cibuilder