feat(gitlab-ci): add what is needed to publish on npm
It is inspired by what exists for CubicWebJS: https://forge.extranet.logilab.fr/cubicweb/cubicwebjs/-/blob/bb645205bf858ee6ae81aed7001f88849f27f600/.gitlab-ci-extended.yml
Note: Tag has to be protected in GitLab to be publishable.