tweak js file

resources/assets/js/bootstrap.js

@@ -25,7 +25,10 @@ window.Vue = require('vue');
  */
 
 window.axios = require('axios');
-window.axios.defaults.headers.common['X-Requested-With'] = 'XMLHttpRequest';
+
+window.axios.defaults.headers.common = {
+    'X-Requested-With': 'XMLHttpRequest'
+};
 
 /**
  * Echo exposes an expressive API for subscribing to channels and listening