Solution to Ubuntu 18.04 Depends: php7.2-fpm but it is not going to be installed Error

If you receive the following error during Virtualmin installation or php7.2 installation on Ubuntu 18.04, it is due to the lack of necessary repository paths in source.list.

nano /etc/apt/source.list
In this section, the necessary repositories are loaded.

deb http://archive.ubuntu.com/ubuntu bionic main multiverse restricted universe
deb http://archive.ubuntu.com/ubuntu bionic-security main multiverse restricted universe
deb http://archive.ubuntu.com/ubuntu bionic-updates main multiverse restricted universe

sudo apt update; sudo apt upgrade -y
sudo apt install php7.2-mbstring