Add recent pattern for ESLinting to repo

Use of all: '.' in Gruntfile.js for eslint config and
eslintIgnore in package.json to ignore linting the "vendor/"
etc directory.

Bug: T203648
Change-Id: I65756ab3b6f413021cedeb22c7933c6cffa2cb78

Gruntfile.js

@@ -10,13 +10,7 @@ module.exports = function ( grunt ) {
 
 	grunt.initConfig( {
 		eslint: {
-			all: [
+			all: '.'
-				'**/*.js',
-				'!lib/**',
-				'!node_modules/**',
-				'!vendor/**',
-				'!resources/js/ext.uls.webfonts.repository.js'
-			]
 		},
 		stylelint: {
 			options: {

package.json

@@ -13,5 +13,10 @@
     "grunt-svgmin": "5.0.0",
     "stylelint": "8.2.0",
     "stylelint-config-wikimedia": "0.4.2"
-  }
+  },
+  "eslintIgnore": [
+    "lib/**",
+    "resources/js/ext.uls.webfonts.repository.js",
+    "vendor/**"
+  ]
 }