Configure your GitLab docker container to listen for HTTPS connections by enabling and configuring the NGINX service.
Learn how to create your own private SSL/TLS certificates.
Automatically create and renew LetsEncrypt SSL certificates on Debian 10 with Certbot.
Learn how to automatically renew your Let's Encrypt SSL certificates on an Ubuntu 18.04 Apache webserver.
Request certificates from LetsEncrypt after having proven that you own the domain.