error in docs

[simonkenyongithub]

in the documentation (https://pub.dev/packages/async_redux#giving-better-error-messages) the code: ` class LogoutAction extends ReduxAction<AppState> {

@override Future<AppState> reduce() async { ... }

@override Object wrapError(error) => LogoutError("Logout failed.", cause: error); }`

is incorrect. the wrapError has a second parameter.