desktop launcher for sudo apt-get update && apt-get upgrade

Create a text file and call it updateme.desktop. Paste the following and save it:

[Desktop Entry]
Version=1.0
Name=update system
Comment=updates system
Exec=bash -c 'sudo apt update && sudo apt upgrade -y; bash'
Terminal=true
Type=Application

Now run chmod +x /path/to/updateme.desktop

Double clicking on the file should now bring up a terminal asking for your password to execute the commands. If you want you can copy it to /usr/share/applications to make it appear in your application's menu.

Thanks to @Terrance for having corrected the Exec command.