copy eslint + tslint from Discord.js (v13)

.github/workflows/lint.yml

@@ -0,0 +1,24 @@
+name: Lint
+on:
+  push:
+    branches: 
+      - '*'
+  pull_request:
+    branches: 
+      - '*'
+jobs:
+  eslint:
+    runs-on: ubuntu-latest
+
+    strategy:
+      matrix:
+        node-version: [16.x]
+
+    steps:
+      - uses: actions/checkout@v2
+      - name: Use Node.js ${{ matrix.node-version }}
+        uses: actions/setup-node@v1
+        with:
+          node-version: ${{ matrix.node-version }}
+      - run: npm ci
+      - run: npm run lint:all