Use full path for certbot-auto in cronjob
On my Debian 10 system, the cronjob for
certbot-auto fails because it can't find certbot-auto. It looks like the default environment used for root's crontab is pretty sparse and doesn't include
/usr/local/bin, so I've changed the cronjob to refer to
certbot-auto by its full path, which fixes the issue and is safer in general.