Add also to
vi /etc/cron.d/munin-plugin-apt
03 * * * * root apt update > /dev/null 2>&1
18 * * * * root apt-get update > /dev/null 2>&1
33 * * * * root apt upgrade > /dev/null 2>&1
48 * * * * root apt-get upgrade > /dev/null 2>&1
# service cron reload
==============================================================
Problems:
:/etc/munin/plugins# munin-run apt
pending.value 3
pending.extinfo file libmagic-mgc libmagic1
hold.value 0
---
:/etc/munin/plugins# munin-run apt_all
pending_stable.value 0
hold_stable.value 0
pending_testing.value 0
hold_testing.value 0
pending_unstable.value 0
hold_unstable.value 0