setup Drupal with Docker: clone repositories via deploy token
The way I handle this is creating a gitlab auth.json file and with your token and using a volume mount to put it into the container.

volumes:
  - /Users/${USER}/.composer/auth.json:/home/wodby/.composer/auth.json # composer auth


In some instances I've wanted my ssh keys in there as well for certain operations, but shouldn't be needed for a pull off gitlab. This is just as easy.

volumes:
- /Users/${USER}/.ssh/id_rsa:/home/wodby/.ssh/id_rsa # ssh