Added Description and Followers to FullPlaylist, fixes #484

Author: JohnnyCrazy

SpotifyAPI.Web/Models/Response/FullPlaylist.cs

@@ -4,7 +4,9 @@ namespace SpotifyAPI.Web
   public class FullPlaylist
   {
     public bool? Collaborative { get; set; }
+    public string? Description { get; set; } = default!;
     public Dictionary<string, string>? ExternalUrls { get; set; } = default!;
+    public Followers Followers { get; set; } = default!;
     public string? Href { get; set; } = default!;
     public string? Id { get; set; } = default!;
     public List<Image>? Images { get; set; } = default!;