Update marginaleffects for the typed fitted-model state #1824

marginaleffects 0.2.2 (model_pyfixest.py) reads _fml, _data, _fixef, _method, _beta_hat (read and write), _coefnames and _vcov. Once the compatible marginaleffects release is out, turn on deprecation warnings for the aliases it reads, including the currently silent _fml, _method and _vcov. The release must land before the next pyfixest release.