File deja-dup-vala-fix.patch of Package deja-dup

diff -urp deja-dup-40.6.orig/deja-dup/widgets/Background.vala deja-dup-40.6/deja-dup/widgets/Background.vala
--- deja-dup-40.6.orig/deja-dup/widgets/Background.vala	2019-12-08 13:17:02.000000000 -0600
+++ deja-dup-40.6/deja-dup/widgets/Background.vala	2022-04-04 13:38:24.431939657 -0500
@@ -75,7 +75,7 @@ public class Background : Object
     return "/org/freedesktop/portal/desktop/request/%s/%s".printf(sender, token);
   }
 
-  void got_response(DBusConnection connection, string sender_name, string object_path,
+  void got_response(DBusConnection connection, string? sender_name, string object_path,
                     string interface_name, string signal_name, Variant parameters)
   {
     Variant values;