Update example

examples/async-data/package.json

@@ -1,8 +1,7 @@
 {
   "name": "nuxt-async-data",
-  "description": "",
   "dependencies": {
-    "axios": "^0.15.2",
+    "axios": "latest",
     "nuxt": "latest"
   },
   "scripts": {

examples/async-data/pages/index.vue

@@ -9,14 +9,9 @@
 
 <script>
 export default {
-  asyncData ({ req }, callback) {
-    setTimeout(function () {
-      // callback(err, data)
-      callback(null, {
+  asyncData: ({ req }) => ({
     userAgent: (req ? req.headers['user-agent'] : navigator.userAgent)
   })
-    }, 100)
-  }
 }
 </script>