Remove GPT mentor link from index.html

Removed link to GPT mentor from the tools section.

index.html

@@ -48,7 +48,6 @@
 						<li><a href="examples/">examples</a></li>
 						<li><a href="docs/">documentation</a></li>
 						<li><a href="https://chromewebstore.google.com/detail/threejs-devtools/jechbjkglifdaldbdbigibihfaclnkbo">devtools</a></li>
-						<li><a href="https://chat.openai.com/g/g-jGjqAMvED-three-js-mentor">gpt</a></li>
 					</ul>
 
 					<h2>Tools</h2>