examples: Use process.server instead

examples/hello-world/pages/about.vue

@@ -7,9 +7,9 @@
 
 <script>
 export default {
-  asyncData ({ isStatic, isServer }) {
+  asyncData () {
     return {
-      name: isStatic ? 'static' : (isServer ? 'server' : 'client')
+      name: process.static ? 'static' : (process.server ? 'server' : 'client')
     }
   }
 }

examples/middleware/middleware/user-agent.js

@@ -1,3 +1,3 @@
 export default function (context) {
-  context.userAgent = context.isServer ? context.req.headers['user-agent'] : navigator.userAgent
+  context.userAgent = process.server ? context.req.headers['user-agent'] : navigator.userAgent
 }