Add 'enclosure' property to 'podcast'.

podcast/podcast.d.ts

@@ -64,6 +64,12 @@ interface IItemOptions
     date: Date;
     lat?: number;
     long?: number;
+    enclosure?: {
+        url: string;
+        file?: string;
+        size?: number;
+        mime?: string;
+    }
     itunesAuthor?: string;
     itunesExplicit?: boolean;
     itunesSubtitle?: string;