installer libssl1.0
# in this part I thought it better to use the add-apt-key tool
sudo apt-get install add-apt-key
sudo su -
add-apt-key --keyserver keyserver.ubuntu.com < the key that appeared in the error >
exit
sudo apt update && apt-cache policy libssl1.0-dev
sudo apt-get install libssl1.0-dev
Plain Pheasant