Update docs/docs/migration-guide.mdx
Update docs/docs/migration-guide.mdx

Co-authored-by: Melinda Loubser <b19ef5eaa25a59f13e6b9938a57f68701f75a998@users.noreply.github.com>
RasaHQ/rasa_nlu,RasaHQ/rasa_nlu,RasaHQ/rasa_nlu