Fix fork button link

Author: clabe45

templates/index.html

@@ -17,7 +17,7 @@ <h3 class="title-text">
     <div>
         <a class="github-button" href="https://github.com/etro-js/etro" data-size="large" data-show-count="true"
            aria-label="Star etro-js/etro on GitHub">Star</a>
-        <a class="github-button" href="https://github.com/etro-js/fork" data-size="large"
+        <a class="github-button" href="https://github.com/etro-js/etro/fork" data-size="large"
            data-show-count="true" aria-label="Fork etro-js/etro on GitHub">Fork</a>
     </div>
 </section>