Multiplatform docker builds

Author: TheKnarf

.github/workflows/releases.yml

@@ -16,19 +16,24 @@ jobs:
     steps:
       - uses: actions/checkout@v2
 
-      - name: Build Docker image
-        run: docker build . --tag "$IMAGE_NAME:${{ github.event.release.tag_name }}"
+      # https://github.com/docker/setup-qemu-action
+      - name: Set up QEMU
+        uses: docker/setup-qemu-action@v1
+
+      # https://github.com/docker/setup-buildx-action
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v1
 
       - name: Log into registry
         run: echo "${{ secrets.DOCKERHUB_PASSWORD }}" | docker login -u $DOCKERHUB_USERNAME --password-stdin
 
-      - name: Push api image
-        run: docker push $IMAGE_NAME:${{ github.event.release.tag_name }}
-
-      - name: Tag as latest and push
+      - name: Build Docker image
         run: |
-          docker tag "$IMAGE_NAME:${{ github.event.release.tag_name}}" $IMAGE_NAME:latest
-          docker push $IMAGE_NAME:latest
+          docker buildx build . \
+          --push \
+          --platform linux/arm/v7,linux/arm64/v8,linux/amd64 \
+          --tag "$IMAGE_NAME:latest" \
+          --tag "$IMAGE_NAME:${{ github.event.release.tag_name}}"
 
 # This action does not yet work with dockerhub personal access token
 # Issue: https://github.com/peter-evans/dockerhub-description/issues/10