[CI] Fix build-release workflow

- Typo in path
- Missing QEMU binaries for cross-platform build

Author: Zerpet

.github/workflows/build-test-publish.yml

@@ -227,7 +227,7 @@ jobs:
       uses: actions/download-artifact@v4
       with:
         name: operator-manifests
-        path: release/
+        path: releases/
     - name: Rename manifest for GCS
       run: mv releases/cluster-operator.yml cluster-operator-${{ env.image_version }}.yml
 
@@ -305,6 +305,12 @@ 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
+
       - name: Login to Docker Hub
         uses: docker/login-action@v3
         with: