chore: added a link to Hacktoberfest in the developer's portal (#89)

src/pages/index.astro

@@ -49,6 +49,12 @@ import RafikiIcon from '../components/logos/RafikiIcon.astro';
           <h2 class="heading--6"><a href="https://github.com/interledger/testnet" data-umami-event="Devs page link - Testnet" target="_blank" rel="noopener noreferrer"><InterledgerIcon /> Test Network Repo</a></h2>
           <p>The Test Network (Testnet) is an open Interledger network working with test money designed for account servicing entities to test their Interledger integration.</p>
         </div>
+
+        <div class="card">
+          <h2 class="heading--6"><a href="https://github.com/interledger/hacktoberfest" data-umami-event="Devs page link - Hacktoberfest" target="_blank" rel="noopener noreferrer"><InterledgerIcon /> Hacktoberfest</a></h2>
+          <p>Join us this October to collaborate on our open source projects.</p>
+        </div>
+
         <div class="card">
           <h2 class="heading--6">Engineering Blog</h2>
           <p>Our team shares their thoughts and experiences on Interledger and the work that we are doing.</p>