We actually don't want to get a daily mail saying /etc/cron.daily/certbot:
Saving debug log to /var/log/letsencrypt/letsencrypt.log
...
Processing /etc/letsencrypt/renewal/fijal.lino-framework.org.conf
... Cert not yet due for renewal
... /etc/letsencrypt/live/static.lino-framework.org/fullchain.pem expires on 2019-07-17 (skipped)
... No renewals were attempted.