update polymer related info to 0.8.7

src/site/docs/tutorials/fetchdata/index.markdown

 ---
 layout: default
 title: "Fetch Data Dynamically"
 description: "Use HttpRequest to fetch data from a file or a server."
 has-permalinks: true
 tutorial:
   id: fetchdata
 next: forms/
 next-title: "Get Input from a Form"
 prev: polymer-intro/
@@ skipping 72 matching lines @@
 and check out the JSON format for each data type.
 
 <iframe class="running-app-frame"
         style="height:500px;width:700px;"
         src="examples/its_all_about_you/out/web/index.html">
 </iframe>
 
 <aside class="alert">
 <strong>Version Note:</strong> The its_all_about_you app
 is compatible with
-<a href="https://pub.dartlang.org/packages/polymer#versions">polymer.dart 0.8.1</a>.
+<a href="https://pub.dartlang.org/packages/polymer#versions">polymer.dart 0.8.7</a>.
 </aside>
 
 The dart:convert library contains two convenient functions
 for working with JSON strings:
 
 | dart:convert function | Description |
 |---|---|
 | <a href="https://api.dartlang.org/dart_convert.html" target="_blank">JSON.decode()</a> | Builds Dart objects from a string containing JSON data. |
 | <a href="https://api.dartlang.org/dart_convert.html" target="_blank">JSON.encode()</a> |  Serializes a Dart object into a JSON string. |
 {: .table}
@@ skipping 351 matching lines @@
 The next tutorial,
 [Get Input from a Form](/docs/tutorials/forms/),
 contains a client/server example that
 shows you how to use a form to get data from the user,
 and using JSON, send that form to a server,
 and handle the server's response.
 
 {% endcapture %}
 
 {% include tutorial.html %}