Add npm script to run linter

Author: yuvipanda

.github/workflows/eslint.yml

@@ -12,4 +12,4 @@ jobs:
     - name: Install modules
       run: npm i
     - name: Run ESLint on binderhub JS
-      run: ./node_modules/.bin/eslint binderhub/static/js
+      run: npm run lint

package.json

@@ -19,7 +19,8 @@
   },
   "scripts": {
     "webpack": "webpack",
-    "webpack:watch": "webpack --watch"
+    "webpack:watch": "webpack --watch",
+    "lint": "eslint binderhub/static/js"
   },
   "repository": {
     "type": "git",