PUBLIC KEY NOT FOUND - WINE

I was getting the error PUBLIC KEY NOT FOUND for WINE when I tried to update Ubuntu.  To fix it I  ran the following four commands in the Terminal.  Hit ENTER after each command and type in your password when prompted.

wget -nc https://dl.winehq.org/wine-builds/winehq.key

sudo apt-key add winehq.key

sudo apt update

sudo apt-get upgrade

This should fix the PUBLIC KEY problem and update your system.  

NOTE:  The first two commands fix the Public Key issue, the last two commands update your software and you can use just them (the last two commands) anytime you want to update your system from the Terminal.