WIP: Update sidekiq-cron 0.6.0 -> 1.0

What does this MR do?

Update sidekiq-cron ruby gem to 1.0 version. diaspora wants to update to this version and we'd like to update sidekiq-cron in debian.

changes https://github.com/ondrejbartas/sidekiq-cron/blob/master/Changes.md

What are the relevant issue numbers?

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Documentation created/updated
• Tests added for this feature/bug
• Tested in all supported browsers
• Conforms to the code review guidelines
• Conforms to the merge request performance guidelines
• Conforms to the style guides
• Conforms to the database guides
• Link to e2e tests MR added if this MR has Requires e2e tests label. See the Test Planning Process.
• Security reports checked/validated by reviewer