Add multi platform build for Docker image

.github/workflows/release.yaml

@@ -50,14 +50,20 @@ jobs:
         id: tag
         run: |
           echo "::set-output name=name::${GITHUB_REF#refs/tags/v}"
+      - name: Set up QEMU
+        uses: docker/setup-qemu-action@v2
+      - name: Set up Docker Buildx
+        id: buildx
+        uses: docker/setup-buildx-action@v2
       - name: Login to DockerHub
-        uses: docker/login-action@v1
+        uses: docker/login-action@v2
         with:
           username: rhysd
           password: ${{ secrets.DOCKERHUB_TOKEN }}
       - name: Build and push
-        uses: docker/build-push-action@v2
+        uses: docker/build-push-action@v3
         with:
+          platforms: linux/amd64,linux/arm64
           build-args: |
             GOLANG_VER=1.18
             ACTIONLINT_VER=${{ steps.tag.outputs.name }}

Dockerfile

@@ -9,8 +9,11 @@ ENV CGO_ENABLED 0
 ARG ACTIONLINT_VER=
 RUN go build -v -ldflags "-s -w -X github.com/rhysd/actionlint.version=${ACTIONLINT_VER}" ./cmd/actionlint
 
+FROM koalaman/shellcheck-alpine:stable as shellcheck
+
 FROM alpine:${ALPINE_VER}
 COPY --from=builder /go/src/app/actionlint /usr/local/bin/
-RUN apk add --no-cache shellcheck py3-pyflakes
+COPY --from=shellcheck /bin/shellcheck /usr/local/bin/shellcheck
+RUN apk add --no-cache py3-pyflakes
 USER guest
 ENTRYPOINT ["/usr/local/bin/actionlint"]