add id to project member user json

app/services/projects/import_export.rb

@@ -17,7 +17,7 @@ module Projects
     private
     def members
-      [{ project_members: { include: [user: { only: [:email, :username] }] } }]
+      [{ project_members: { include: [user: { only: [:id, :email, :username] }] } }]
     end
     def storage_path