Update index.html with image alt text

Author: BothXP

Chapter2/Amazeriffic/index.html

@@ -26,7 +26,7 @@ <h3>Here's why you need Amazeriffic</h3>
         <li>It rocks your world</li>
       </ul>
 
-      <img src="lightbulb.png">
+      <img src="lightbulb.png" alt="an image of a lightbulb">
     </main>
 
     <footer>