Fix library not loading due to a bug with covers

mopidy_funkwhale/library.py

@@ -333,7 +333,7 @@ def convert_to_artist(payload, uri_prefix="funkwhale:artists"):
 @cast_to_ref
 def convert_to_album(payload, uri_prefix="funkwhale:albums"):
     artist = convert_to_artist(payload["artist"])
-    image = payload["cover"]["original"] if payload["cover"] else None
+    image = payload["cover"]["urls"]["original"] if payload["cover"] else None
 
     return models.Album(
         uri=uri_prefix + ":%s" % payload["id"],