feat: add frontend linter

.github/workflows/lint.yml

@@ -0,0 +1,17 @@
+name: CI
+on: push
+jobs:
+  eslint:
+    runs-on: ubuntu-latest
+    defaults:
+      run:
+        working-directory: ./frontend
+    steps:
+      - uses: actions/checkout@v2
+      - uses: actions/setup-node@v2
+        with:
+          node-version: "20.5.1"
+      - name: install
+        run: yarn install
+      - name: ESLint
+        run: eslint --ext .ts,.tsx ./app