Fix typo in tech overview

Thanks @euangoddard! 🎩 [skip ci] 9ff8fa5

tech-overview.html

@@ -172,7 +172,7 @@ <h2 id="introduction">Introduction</h2>
     <source src="/assets/diagrams/centralised-server_to_user.mp4" type="video/mp4" />
 </video>
 
-<p>Note that in the animation above, Bob is using a different Internet gateway (<code class="language-plaintext highlighter-rouge">london.relaycorp.cloud</code>) than Alice (<code class="language-plaintext highlighter-rouge">frankfurt.relaycorp.tech</code>). As a federated network, users can choose their own Internet gateway independently of the service they use and the people they communicate with – Think of it as the Awala equivalent of an ISP.</p>
+<p>Note that in the animation above, Bob is using a different Internet gateway (<code class="language-plaintext highlighter-rouge">london.relaycorp.cloud</code>) than Alice (<code class="language-plaintext highlighter-rouge">frankfurt.relaycorp.cloud</code>). As a federated network, users can choose their own Internet gateway independently of the service they use and the people they communicate with – Think of it as the Awala equivalent of an ISP.</p>
 
 <h2 id="sneakernet">Sneakernet</h2>
 
@@ -328,7 +328,7 @@ <h3 id="internet-node-connection-parameters">Internet node connection parameters
 <p>Internet endpoints and Internet gateways expose their connection parameters via their parcel delivery and gateway synchronisation <a href="#message-transport-bindings">bindings</a>, respectively. Such parameters are:</p>
 
 <ul>
-  <li>The Internet address of the node (e.g., <code class="language-plaintext highlighter-rouge">frankfurt.relaycorp.tech</code>).</li>
+  <li>The Internet address of the node (e.g., <code class="language-plaintext highlighter-rouge">frankfurt.relaycorp.cloud</code>).</li>
   <li>The identity public key of the node.</li>
   <li>The initial ECDH public key of the node.</li>
 </ul>