The API documentation is automatically posted by the gitlab pipeline. However, it needs a runner to be performed. (see gitlab runner).
The project should be under the benefit of “free premium” gitlab as an open software project. Thus, granting access to free shared runners for continuous integration. The pipeline should then execute automatically.
If the shared runners doesn't work, it is possible to run a runner locally.
To run the pipeline on a local runner:
gitlab-runner register
And this registration token: GR1348941S7fLVNwyWxK_pjTbRKKs
the tags should be docker
with alpine:latest
as default image
Then, run the runner with gitlab-runner run