Add artifacts expiry time for GitLab.com (!19520) · Merge requests · GitLab.org / GitLab FOSS · GitLab

Achilleas Pipinellis - OOO until November 25th (parental leave) requested to merge docs/gitlab-com-artifacts-expire into master Jun 07, 2018

What does this MR do?

Document the value for expiring artifacts on .com.