New: Send TrackFile in Webhook retag payload

Fixes #2533

src/NzbDrone.Core/Notifications/Webhook/Webhook.cs

@@ -87,7 +87,8 @@ namespace NzbDrone.Core.Notifications.Webhook
             var payload = new WebhookRetagPayload
             {
                 EventType = WebhookEventType.Retag,
-                Artist = new WebhookArtist(message.Artist)
+                Artist = new WebhookArtist(message.Artist),
+                TrackFile = new WebhookTrackFile(message.TrackFile)
             };
 
             _proxy.SendWebhook(payload, Settings);

src/NzbDrone.Core/Notifications/Webhook/WebhookRetagPayload.cs

@@ -3,5 +3,6 @@ namespace NzbDrone.Core.Notifications.Webhook
     public class WebhookRetagPayload : WebhookPayload
     {
         public WebhookArtist Artist { get; set; }
+        public WebhookTrackFile TrackFile { get; set; }
     }
 }