BREAKING CHANGE: quiqqer v2 has been renamed to quiqqer/core. a new major version will be created here so that we can still develop for both versions.

refactor: replace mtdowling/cron-expression with dragonmantank/cron-expression #54

The package was required to automatically add it's cron.
Since the auto-create feature exists now, it is no longer required.

related: quiqqer/package-cron#44