change lastresponse to last-response in dom-bind example

src/lib/template/dom-bind.html

@@ -34,7 +34,7 @@
 
   <template is="dom-bind">
 
-    <iron-ajax url="http://..." lastresponse="{{data}}" auto></iron-ajax>
+    <iron-ajax url="http://..." last-response="{{data}}" auto></iron-ajax>
 
     <template is="dom-repeat" items="{{data}}">
         <div><span>{{item.first}}</span> <span>{{item.last}}</span></div>