Add s390x support with docker buildx

.github/workflows/build.yml

@@ -17,7 +17,21 @@ jobs:
     name: Build
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v1
-
-    - name: Build the Docker image
-      run: docker build .
+      - name: Checkout code
+        uses: actions/checkout@v2
+
+      - name: Set up Docker Buildx
+        id: buildx
+        uses: docker/setup-buildx-action@v1
+
+      - name: Set up QEMU
+        uses: docker/setup-qemu-action@v1
+
+      - name: Build and Push
+        id: docker_build
+        uses: docker/build-push-action@v2
+        with:
+          context: .
+          file: ./Dockerfile
+          platforms: linux/amd64,linux/s390x
+          push: false