fix: demo using custom controls for YouTube

demo/src/js/demo.js

@@ -59,7 +59,6 @@ import toggleClass from './toggle-class';
       },
       previewThumbnails: {
         enabled: true,
-        customControls: true,
         src: ['https://cdn.plyr.io/static/demo/thumbs/100p.vtt', 'https://cdn.plyr.io/static/demo/thumbs/240p.vtt'],
       },
       vimeo: {
@@ -67,6 +66,9 @@ import toggleClass from './toggle-class';
         // Prevent Vimeo blocking plyr.io demo site
         referrerPolicy: 'no-referrer',
       },
+      youtube: {
+        customControls: true,
+      },
     });
 
     // Expose for tinkering in the console