Fix microsite footer link

Thanks to Adam Šilhan for reporting the broken link.

microsite/index.html

@@ -67,7 +67,7 @@ <h2>Sample Ratio Mismatch (SRM) Checker</h2>
               <p class="text-center">This extension automatically performs the Sample Ratio Mismatch test and flags potential issues on supported experimentation platforms.</p>
 
               <footer class="text-center">
-                <small>Designed with <i class="glyphicon glyphicon-heart"></i> by <a href="www.lukasvermeer.nl" target="_blank">Lukas Vermeer</a> for experimenters everywhere</small>
+                <small>Designed with <i class="glyphicon glyphicon-heart"></i> by <a href="https://www.lukasvermeer.nl" target="_blank">Lukas Vermeer</a> for experimenters everywhere</small>
               </footer>
             </div>
           </div>