chore(ci): add QEMU and Docker Buildx setup for multi-platform builds in GitHub Actions

Author: lltx

.github/workflows/docker-build.yml

@@ -17,6 +17,12 @@ jobs:
       - name: Checkout repository
         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: Log in to the Container registry
         uses: docker/login-action@v3
         with:
@@ -28,6 +34,7 @@ jobs:
         with:
           context: .
           push: true
+          platforms: linux/amd64,linux/arm64
           tags: |
             pig4cloud/markitdown:latest
           build-args: |