Add linting to GitHub actions

.github/workflows/lint.yml

@@ -0,0 +1,13 @@
+name: Lint
+ 
+on: [push]
+ 
+jobs:
+  lint:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v1
+    - name: Install Node dependencies
+      run: npm install
+    - name: Run linter
+      run: npm run lint