fix: ensure the reuse job is always run
.pre stage is not guaranteed to always execute.
In particular, if there are no jobs defined/enabled outside the
.post stages then no jobs will be executed at all, regardless of whether there are jobs enabled in
E.g.: a project which does not define custom jobs and only references the
ci-reuse.yml template in the
.gitlab-ci.yml file would trigger this scenario.
ci-reuse.yml is an explicit opt-in, let's ensure that if a project does opt-in it will always run.