fix: add qemu and fix release multiarch

Signed-off-by: Alice Lilith <alice@ngrok.com>

Author: Alice-Lilith

.github/workflows/release.yaml

@@ -27,11 +27,14 @@ jobs:
         with:
           go-version-file: backend/go.mod
 
+      - name: Set up QEMU
+        uses: docker/setup-qemu-action@v3
+
       - id: buildx-setup
         name: Set up Docker Buildx
         uses: docker/setup-buildx-action@v3
         with:
-          platforms: linux/amd64
+          platforms: ${{ env.DOCKER_BUILDX_PLATFORMS }}
 
       - name: Fetch git tag
         id: git-tag