**needs labels:** `ci` and `artifacts` === I loved the new feature of 8.9 about artifact expiration date (http://docs.gitlab.com/ce/ci/yaml/README.html#artifactsexpire_in) but I think Gitlab needs an extra configuration on artifacts retention policy. Do you think a `last n builds` retention policy would be useful? We could thus have a config like: ``` job: artifacts: expire_in: 1 week keep_last: 3 ``` To have artifacts expire after 1 week of age but always keep the last 3 builded artifacts. What do you think?