feat(home): update hero video (#558)

## What

Replace the YouTube video embedded in the homepage hero section with a
new one (https://www.youtube.com/watch?v=UBppH7GqQTA).

Updated both the desktop and mobile iframe embeds in
`layouts/shortcodes/blocks/hero.html`.

## Why

Refresh the hero with the latest video.

Author: kvaps

layouts/shortcodes/blocks/hero.html

@@ -71,7 +71,7 @@
             <!-- Video for mobile devices -->
             <div class="hero-video-mobile d-lg-none mt-4">
               <div class="ratio ratio-16x9">
-                <iframe src="https://www.youtube-nocookie.com/embed/Nm6HKDK-XD4?rel=0&modestbranding=1" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share" allowfullscreen></iframe>
+                <iframe src="https://www.youtube-nocookie.com/embed/UBppH7GqQTA?rel=0&modestbranding=1" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share" allowfullscreen></iframe>
               </div>
             </div>
           </div>
@@ -80,7 +80,7 @@
         <div class="col-lg-6 d-none d-lg-block">
           <div class="hero-image">
             <div class="ratio ratio-16x9">
-              <iframe src="https://www.youtube-nocookie.com/embed/Nm6HKDK-XD4?rel=0&modestbranding=1" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share" referrerpolicy="strict-origin-when-cross-origin" allowfullscreen></iframe>
+              <iframe src="https://www.youtube-nocookie.com/embed/UBppH7GqQTA?rel=0&modestbranding=1" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share" referrerpolicy="strict-origin-when-cross-origin" allowfullscreen></iframe>
             </div>
           </div>
         </div>