Ubuntu 18.04.6 LTSわよ
$ sudo apt update && apt list --upgradable
:
libmysqlclient20/bionic-updates,bionic-security 5.7.38-0ubuntu0.18.04.1 amd64 [upgradable from: 5.7.37-0ubuntu0.18.04.1]
:
$ sudo apt dist-upgrade -y
$ cat /var/run/reboot-required*
cat: '/var/run/reboot-required*': No such file or directory
ヨシ