Added .default to Vue component requires

JeffreyWay mentioned this in the "Breaking" section here: https://github.com/JeffreyWay/laravel-mix/releases/tag/v4.0.0
with a matching commit here: laravel/laravel@dc58f95
to finally a PR here: laravel/laravel@dc58f95#diff-b7c96b83e41797041ea5067055f8b2af

Without this change upon a new clone you would get a `[Vue warn]: Failed to mount component: template or render function not defined.` error in the console.

Author: belzaaron

resources/js/frontend/app.js

@@ -20,9 +20,9 @@ window.Vue = Vue;
  */
 
 // const files = require.context('./', true, /\.vue$/i)
-// files.keys().map(key => Vue.component(key.split('/').pop().split('.')[0], files(key)))
+// files.keys().map(key => Vue.component(key.split('/').pop().split('.')[0], files(key).default))
 
-Vue.component('example-component', require('./components/ExampleComponent.vue'));
+Vue.component('example-component', require('./components/ExampleComponent.vue').default);
 
 /**
  * Next, we will create a fresh Vue application instance and attach it to