Setup reviewdog in GitHub Actions

.github/workflows/reviewdog.yml

@@ -0,0 +1,25 @@
+name: reviewdog
+
+on:
+  pull_request:
+
+jobs:
+  eslint:
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@master
+    - name: Use Node.js 16.x
+      uses: actions/setup-node@v1
+      with:
+        node-version: '16.x'
+        registry-url: 'https://registry.npmjs.org'
+    - name: Install dependencies
+      run: |
+        yarn install
+    - uses: reviewdog/action-setup@v1
+    - name: Run eslint
+      env:
+        REVIEWDOG_GITHUB_API_TOKEN: ${{ github.token }}
+      run: |
+        yarn workspace megalodon lint | reviewdog -f=eslint -reporter=github-pr-review