ci: add arm64 build workflow

.github/workflows/build-arm64.yml

@@ -0,0 +1,25 @@
+name: build (arm64)
+
+on: [push]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v3
+
+    - name: Set up Docker buildx
+      uses: docker/setup-buildx-action@v1
+
+    - name: Build ARM64 image
+      run: |
+        docker build --platform=linux/arm64 -t arm64-env .
+        
+    - name: Run ARM64 container
+      run: |
+        docker run --platform=linux/arm64 \
+          --rm \
+          -v "${{ github.workspace }}":/workspace \
+          arm64-env \
+          make arm64