Notifications for failed cron jobs

Cron jobs are a vital part of every sysadmins setup. Backups, log rotation, certificate renewal and whatnot. I've mostly just relied on them working as they should until now, but with my recent Huginn + Matrix obsession I figured I should have some sort of notifications. Crontab supports sending emails for your jobs, all you have to do is add at the top. It defaults (on most distros) to sendmail, which I discovered was kind of a pain to set up. Instead I found t