Build aarch64-linux image under QEMU emulation for linux/arm64

.github/workflows/ci.yml

@@ -43,10 +43,35 @@ jobs:
           ruby-version: "3.0"
           bundler-cache: true # runs 'bundle install' and caches installed gems automatically
 
+      - name: Set up Docker Buildx
+        id: buildx
+        uses: docker/setup-buildx-action@v1
+        with:
+          install: true
+        if: matrix.platform == 'aarch64-linux'
+
+      - name: Enable Multiarch
+        run: |
+          docker run --rm --privileged multiarch/qemu-user-static --reset -p yes
+        if: matrix.platform == 'aarch64-linux'
+
+      - name: Create builder
+        run: |
+          docker buildx create --name mbuilder
+          docker buildx use mbuilder
+          docker buildx inspect
+          docker buildx ls
+        if: matrix.platform == 'aarch64-linux'
+
+      - name: Export Docker Buildx arguments
+        run: |
+          echo "DOCKER_BUILDX_ARGS=--platform=linux/arm64" >> $GITHUB_ENV
+        if: matrix.platform == 'aarch64-linux'
+
       - name: Build docker image
         run: |
           docker buildx create --driver docker-container --use
-          bundle exec rake build:${PLATFORM} RCD_DOCKER_BUILD="docker buildx build --cache-from=type=local,src=tmp/build-cache --cache-to=type=local,dest=tmp/build-cache-new --load"
+          bundle exec rake build:${PLATFORM} RCD_DOCKER_BUILD="docker buildx build ${DOCKER_BUILDX_ARGS} --cache-from=type=local,src=tmp/build-cache --cache-to=type=local,dest=tmp/build-cache-new --load"
 
       - name: Move build cache and remove outdated layers
         run: |