Update CDN version numbers

docs/index.html

@@ -71,8 +71,8 @@ slug: home
         section of your HTML.
 
 <pre class="code">
-&lt;link href="//cdnjs.cloudflare.com/ajax/libs/select2/4.0.0-beta.3/css/select2.min.css" rel="stylesheet" /&gt;
-&lt;script src="//cdnjs.cloudflare.com/ajax/libs/select2/4.0.0-beta.3/js/select2.min.js"&gt;&lt;/script&gt;
+&lt;link href="//cdnjs.cloudflare.com/ajax/libs/select2/4.0.0-rc.1/css/select2.min.css" rel="stylesheet" /&gt;
+&lt;script src="//cdnjs.cloudflare.com/ajax/libs/select2/4.0.0-rc.1/js/select2.min.js"&gt;&lt;/script&gt;
 </pre>
 
         <div class="alert alert-info">