fix: correct closing tag

Author: dkarczmarski

content/en/_index.html

@@ -50,7 +50,7 @@ <h2>The Absolute Beginner's Guide To Cloud Native</h2>
 </div>
 {{< /blocks/section >}}
 {{< blocks/section id="upcoming-events" >}}
-<h2>Attend upcoming KubeCon + CloudNativeCon events</h3>
+<h2>Attend upcoming KubeCon + CloudNativeCon events</h2>
   <!-- TODO: change this to a shortcode that auto-updates from a schedule -->
   <div>
     <a href="https://events.linuxfoundation.org/kubecon-cloudnativecon-north-america/" class="desktopKCButton"><strong>North America</strong> (Atlanta, Nov 10-13)</a>