youtube thumbnail size - set to maxresdefault

vue-theme/src/utils/helpers.js

 
     // Uncomment to see what the url transformer is finding
     // console.log('video:', videoId[0])
-    let size = '0'
+    let size = 'maxresdefault'
     switch (desiredSize) {
         case 'medium':
             size = 'mqdefault'