Add eslint to gh workflow

Author: njxue

.github/workflows/frontend.yml

@@ -0,0 +1,34 @@
+name: Frontend CI
+
+on:
+  push:
+    branches:
+      - main
+    paths:
+      - "frontend/**"
+  pull_request:
+    branches:
+      - main
+    paths:
+      - "frontend/**"
+
+jobs:
+  Run ESLint:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v3
+
+      - name: Setup Node.js
+        uses: actions/setup-node@v3
+        with:
+          node-version: "18.x"
+
+      - name: Install dependencies
+        run: npm ci
+        working-directory: frontend
+
+      - name: Run ESLint
+        run: npm lint
+        working-directory: frontend