debian/apertis/gitlab-ci.yml: Drop since we use an external definition
Apertis has moved to using external references in the CI config path setting for the packagign repositories, so the gitlab-ci.yml embedded in the repository is no longer needed.
🟡 v2023.5 entered Soft Feature Freeze, no additional features will be accepted • schedule
Apertis has moved to using external references in the CI config path setting for the packagign repositories, so the gitlab-ci.yml embedded in the repository is no longer needed.