Add comment describing jellyfin image tag invalidation

src/shared/api/jellyfin/jellyfin-normalize.ts

@@ -89,6 +89,8 @@ const getSongCoverArtUrl = (args: {
             '/Images/Primary' +
             `?width=${size}` +
             '&quality=96' +
+            // Invalidate the cache if the image chances. This appears to be
+            // how Jellyfin Web does it as well
             `&tag=${args.item.ImageTags.Primary}`
         );
     }