How to deploy a Laravel app to Heroku with GitLab CI/CD

This post is exactly about what the title said: deploying a Laravel application to Heroku with GitLab CI/CD.

As I needed to do it I unfortunately didn’t manage to find any tutorial or post about this precise case. I had thus to gather information here and there and thought it could be a good thing to write about it so it could help anyone who would find itself in this…