[FIX] website_event: demo data description

The title of the events states 5 days training while the full description
explains the plan of a 3 days training on Odoo

Courtesy of Mathias Neef

addons/website_event/data/event_demo.xml

@@ -19,8 +19,8 @@
                         <img alt="Banner Odoo Image" class="img-responsive" src="/website/static/src/img/banner/banner_picture.png" style=""/>
                     </div>
                     <div class="carousel-content col-sm-12 col-md-5 mt32" style="text-align: center; color: white;">
-                        <h2>5 Intensive Days</h2>
-                        <h4>to learn .JS development</h4>
+                        <h2>3 Intensive Days</h2>
+                        <h4>to learn Odoo Programming</h4>
                     </div>
                 </div>
             </div>