Add QEMU setup for multi-arch Docker builds

.gitea/workflows/ci.yml

@@ -37,6 +37,9 @@ jobs:
       - name: Checkout
         uses: actions/checkout@v4
 
+      - name: Set up QEMU
+        uses: docker/setup-qemu-action@v3
+
       - name: Set up Docker Buildx
         uses: docker/setup-buildx-action@v3