`2-99-maintenance` branch does not have `rspec-support` dependency and  the [`expect_deprecation_with_call_site`](https://github.com/rspec/rspec-mocks/blob/7b888d0003bb70e04f8434e5feb7211240dbe090/spec/spec_helper.rb#L24) in `2-99-maintenance` does not support message matching. It seems I need to copy & paste from `rspec-support`.