build for armv7 too

.github/workflows/build.yml

@@ -14,6 +14,13 @@ jobs:
         with:
           fetch-depth: 0
 
+      # Setup
+      - name: Set up QEMU
+        uses: docker/setup-qemu-action@v2
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v2
+
       - name: Set up Java
         uses: actions/setup-java@v3
         with:
@@ -21,6 +28,7 @@ jobs:
           distribution: "temurin"
           cache: "maven"
 
+      # Build
       - name: Build with Maven
         run: mvn --batch-mode --update-snapshots verify
 
@@ -42,6 +50,7 @@ jobs:
         uses: docker/build-push-action@v4
         with:
           context: .
+          platforms: linux/amd64,linux/arm/v7
           push: ${{ github.ref_type == 'tag' && matrix.java == '8' }}
           tags: |
             athou/commafeed:latest