Add support for arm/v7 platform in QEMU setup for Docker workflow

Author: tacxou

.github/workflows/docker-image.yml

@@ -21,6 +21,8 @@ jobs:
 
       - name: Set up QEMU
         uses: docker/setup-qemu-action@v3
+        with:
+          platforms: linux/arm/v7
 
       - name: Log in to the Container registry
         uses: docker/login-action@65b78e6e13532edd9afa3aa52ac7964289d1a9c1