Update index.html.twig

Resources/views/Examples/index.html.twig

@@ -29,7 +29,7 @@
 	        <h2>what it is made of</h2>
 	        <ul>
 	            <li><a href="http://www.symfony.com">Symfony2</a></li>
-	            <li><a href="http://twitter.github.com/bootstrap/">bootstrap2</a></li>
+	            <li><a href="http://getbootstrap.com/">Bootstrap3</a></li>
 	            <li>and a lot more</li>
 	        </ul>
 	    </div>