Vereinfacht: sync country with finance contact API

lib/mv/vereinfacht/changes/sync_contact.ex

@@ -9,7 +9,7 @@ defmodule Mv.Vereinfacht.Changes.SyncContact do
   (Mv.Config.vereinfacht_configured?/0).
 
   Only runs when relevant data changed: on create always; on update only when
-  first_name, last_name, email, street, house_number, postal_code, or city changed,
+  first_name, last_name, email, street, house_number, postal_code, city, or country changed,
   or when the member has no vereinfacht_contact_id yet (to avoid unnecessary API calls).
   """
   use Ash.Resource.Change
@@ -26,7 +26,8 @@ defmodule Mv.Vereinfacht.Changes.SyncContact do
     :street,
     :house_number,
     :postal_code,
-    :city
+    :city,
+    :country
   ]
 
   @impl true