Resolve "GitlabUsagePingWorker is not running on GitLab.com"

What does this MR do?

Schedule the usage ping worker to happen every minute in a random ten-minute period, on a random hour, on a Sunday 🙂

Are there points in the code the reviewer needs to double check?

I tested the case with a leading zero manually, and it works fine:

Rufus::Scheduler::CronLine.new('00-09 7 * * 0').previous_time
#=> #<EtOrbi::EoTime:0x007fccce69b5c0
# @seconds=1507446540.0,
# @time=2017-10-08 07:09:00 UTC,
# @zone=#<TZInfo::TimezoneProxy: Etc/UTC>>
Rufus::Scheduler::CronLine.new('00-09 7 * * 0').next_time
#=> #<EtOrbi::EoTime:0x007fcccce2c0e8
# @seconds=1508050800.0,
# @time=2017-10-15 07:00:00 UTC,
# @zone=#<TZInfo::TimezoneProxy: Etc/UTC>>

Why was this MR needed?

It looks like we sometimes miss cron jobs: https://gitlab.com/gitlab-org/gitlab-ce/issues/39017

This isn't a real fix, but if this works, then my guesses in that issue might be correct.

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Review
  • Has been reviewed by Backend

What are the relevant issue numbers?

#39017 (closed).