Cron jobs for scheduled backups are not launched due to insecure permissions

[mspanc]

Hello, I use dokku 0.8.0 on ubuntu 16.04 with the most recent version of the postgresql plugin and I have found out that scheduled backups are not launched.

In the logs I have the following messages

Jan 11 13:30:01 dokku-ovh1-002 cron[754]: (*system*dokku-postgres-plumber-prod) INSECURE MODE (group/other writable) (/etc/cron.d/dokku-postgres-plumber-prod)
Jan 11 13:30:01 dokku-ovh1-002 cron[754]: (*system*dokku-postgres-agenda-prod) INSECURE MODE (group/other writable) (/etc/cron.d/dokku-postgres-agenda-prod)

Indeed, created files are group-writable:

# ls -l /etc/cron.d/
total 20
-rw-rw-r-- 1 root root  53 Jan 10 17:21 dokku-postgres-agenda-prod
-rw-rw-r-- 1 root root  54 Jan 10 17:10 dokku-postgres-plumber-prod
-rw-rw-r-- 1 root root  52 Jan 10 16:36 dokku-postgres-vault-prod
-rw-r--r-- 1 root root 589 Jul 16  2014 mdadm
-rw-r--r-- 1 root root 191 Jan 12  2016 popularity-contest