feat: Add Prettier check to GitHub Actions workflo

.github/workflows/ci.yml

@@ -0,0 +1,28 @@
+# .github/workflows/ci.yml
+name: CI
+
+on: [push, pull_request]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v2
+
+    - name: Use Node.js
+      uses: actions/setup-node@v2
+      with:
+        node-version: '14'
+
+    - name: Install dependencies
+      run: pnpm install
+
+    - name: Run eslint
+      run: npx eslint . --ext .js,.ts
+
+    - name: Run tests
+      run: pnpm run test
+
+    - name: Run Prettier
+      run: npx prettier --write {file_path}