Update docs/user-guide/docker/building-in-docker.rst
Update docs/user-guide/docker/building-in-docker.rst

Co-Authored-By: Akela Drissner-Schmid <afb3657645c958bf169590c5b33a84e72c1baeac@users.noreply.github.com>
RasaHQ/rasa_nlu,RasaHQ/rasa_nlu,RasaHQ/rasa_nlu