Plausible tracking

Hi,

I host my GitLab with Docker. I’d like to add a Plausible (like Matomo) snippet to the headers but can’t find a way to do this.
I use NPM as reverse proxy.

I read many blogs, forum posts about gitlab.rb config but can’t find any way to integrate my snippet:

<script defer data-domain="gitlab.xx.xx" src="https://plausible.xx.xx/js/plausible.js"></script>

Any kind help would be really appreciated!
Thanks,
A.