Make canary.gitlab.com reflect `master`

This is one of several issues required to be solved to unblock https://gitlab.com/gitlab-org/gitlab-ce/issues/34877

Per https://gitlab.com/gitlab-com/infrastructure/issues/1944#note_37505913, we should have nightly builds of master available, and @rspeicher was going to look in to what is required to deploy these packages to canary.gitlab.com on a daily basis.