Updated dependencies to latest versions.
Merge pull request #28 from alphagov/feature/update-deps

Updated dependencies to latest versions.
Reduce hourly limit to 58mins

This is because the cron job runs every hour so the timing is never quite right. If we shift the time to 58mins it will notify on the hour when needed.
Merge pull request #29 from alphagov/bugfix/frequency

Reduce hourly limit to 58mins