Fix link to CoC

Author: adeen-s

_layouts/hackathon.html

@@ -224,7 +224,7 @@ <h1 class="title has-text-left" style="font-size:3vh !important;">
 
 <p>Come and join over 150 like-minded students contributing to open-source during a weekend to make something amazing!</p>
 
-<p>Please keep in mind our <a href="/coc.md">code of conduct</a>.</p>
+<p>Please keep in mind our <a href="/coc.html">code of conduct</a>.</p>
 
       </div>
     </section>