fix a broken link

Author: SkypLabs

index.html

@@ -355,7 +355,7 @@ <h2>Common features</h2>
 					<h2>Want to know more about Git ?</h2>
 					<p><a href="http://git-scm.com/docs">Official documentation</a></p>
 					<p><a href="http://git-scm.com/book/en/v2">Pro Git, 2nd edition</a></p>
-					<p><a href="https://training.github.com/kit/downloads/github-git-cheat-sheet.pdf">Cheat sheet</a></p>
+					<p><a href="https://services.github.com/on-demand/downloads/github-git-cheat-sheet.pdf">Cheat sheet</a></p>
 					<p><a href="http://git-scm.com/videos">Videos</a></p>
 				</section>