Allow `jobs keys` to default to listing all keys (#252)
Allow `jobs keys` to default to listing all keys (#252)

This can help debug Windows installations, where the Windows CLI
interacts poorly with `bundle exec jobs keys '*'`:

ERROR: "jobs keys" was called with arguments [ (every file in the working directory ) ]
mhenrixon/sidekiq-unique-jobs,mhenrixon/sidekiq-unique-jobs,mhenrixon/sidekiq-unique-jobs,mhenrixon/sidekiq-unique-jobs