Install gnome-packagekit-session by entering the following commands in the terminal:
sudo apt update sudo apt install gnome-packagekit-session
Description:
Transitional package (gnome-packagekit-session -> gnome-software)
Transitional dummy package replacing gnome-packagekit-session with gnome-software. . The PackageKit session interface is no separate component anymore, but built into GNOME-Software.
Homepage: https://wiki.gnome.org/Apps/Software
Version: 3.28.1-0ubuntu4
Section: universe/oldlibs