Update public/index.html

public/index.html

@@ -13,7 +13,7 @@
       <a href="https://gitlab.com/pages/">Other Examples</a>
     </div>
 
-    <h1>Hello World!</h1>
+    <h1>Coucou</h1>
 
     <p>
       This is a simple plain-HTML website on GitLab Pages, without any fancy static site generator.