added link to cheat sheet for py2/3 compatibility
added link to cheat sheet for py2/3 compatibility

PHLF/rasa_nlu,RasaHQ/rasa_nlu,verloop/rasa_nlu,verloop/rasa_nlu,RasaHQ/rasa_nlu,RasaHQ/rasa_nlu,PHLF/rasa_nlu,beeva-fernandocerezal/rasa_nlu,beeva-fernandocerezal/rasa_nlu