update select2 example

examples/select2/index.html

@@ -4,9 +4,9 @@
     <meta charset="utf-8">
     <title>Vue.js custom directive integration example (select2)</title>
     <script src="../../dist/vue.js"></script>
-    <script src="https://code.jquery.com/jquery-2.1.4.min.js"></script>
-    <link href="https://cdnjs.cloudflare.com/ajax/libs/select2/4.0.0/css/select2.min.css" rel="stylesheet">
-    <script src="https://cdnjs.cloudflare.com/ajax/libs/select2/4.0.0/js/select2.min.js"></script>
+    <script src="https://unpkg.com/jquery"></script>
+    <script src="https://unpkg.com/select2@4.0.3"></script>
+    <link href="https://unpkg.com/select2@4.0.3/dist/css/select2.min.css" rel="stylesheet">
     <style>
       html, body {
         font: 13px/18px sans-serif;
@@ -21,6 +21,7 @@
     <div id="el">
     </div>
 
+    <!-- using string template here to work around HTML <option> placement restriction -->
     <script type="text/x-template" id="demo-template">
       <div>
         <p>Selected: {{ selected }}</p>