fix: exclude tests directory entirely

mentioned in merge request pmv!80 (closed)

mentioned in merge request !36 (closed)

mentioned in merge request common-ci-tasks!147 (closed)

mentioned in merge request cmbr!61 (closed)

mentioned in merge request asdf-promtool!21 (closed)

mentioned in merge request common-ci-tasks!163 (closed)

mentioned in merge request pmv!97 (closed)

mentioned in merge request cmbr!79 (closed)

mentioned in merge request third-party-container-images!91 (closed)

mentioned in merge request third-party-container-images!92 (closed)