Add PublishDate to Potato feed for Radarr (#934)

src/Jackett/Controllers/PotatoController.cs

@@ -146,7 +146,8 @@ namespace Jackett.Controllers
                         type = "movie",
                         size = (long)release.Size / (1024 * 1024), // This is in MB
                         leechers = (int)release.Peers - (int)release.Seeders,
-                        seeders = (int)release.Seeders
+                        seeders = (int)release.Seeders,
+                        publish_date = release.PublishDate
                     });
                 }
             }

src/Jackett/Models/TorrentPotatoResponseItem.cs

@@ -18,5 +18,6 @@ namespace Jackett.Models
         public long size { get; set; }
         public int leechers { get; set; }
         public int seeders { get; set; }
+        public DateTime publish_date { get; set; }
     }
 }