CI: Add darwin-arm64 via MacStadium-based runner

.github/workflows/ci-darwin-arm64v8.yml

@@ -0,0 +1,27 @@
+name: CI (MacStadium)
+on:
+  - push
+  - pull_request
+jobs:
+  CI:
+    runs-on: macos-m1
+    defaults:
+      run:
+        shell: /usr/bin/arch -arch arm64e /bin/bash -l {0}
+    steps:
+      - name: Dependencies
+        uses: actions/setup-node@v2
+        with:
+          node-version: 16
+          architecture: arm64
+      - name: Checkout
+        uses: actions/checkout@v2
+      - name: Install
+        run: npm install --build-from-source --unsafe-perm
+      - name: Test
+        run: npm test
+      - name: Prebuild
+        if: startsWith(github.ref, 'refs/tags/')
+        env:
+          prebuild_upload: ${{ secrets.GITHUB_TOKEN }}
+        run: npx prebuild --runtime napi --target 5

.github/workflows/ci.yml

@@ -1,3 +1,4 @@
+name: CI (GitHub)
 on:
   - push
   - pull_request