More warning fixes

MediaBrowser.Controller/Providers/SongInfo.cs

@@ -1,12 +1,15 @@
 using System;
+using System.Collections.Generic;
 
 namespace MediaBrowser.Controller.Providers
 {
     public class SongInfo : ItemLookupInfo
     {
-        public string[] AlbumArtists { get; set; }
+        public IReadOnlyList<string> AlbumArtists { get; set; }
+
         public string Album { get; set; }
-        public string[] Artists { get; set; }
+
+        public IReadOnlyList<string> Artists { get; set; }
 
         public SongInfo()
         {