wget https://github.com/shiftkey/desktop/releases/download/release-3.1.1-linux1/GitHubDesktop-linux-3.1.1-linux1.deb
sudo gdebi GitHubDesktop-linux-3.1.1-linux1.deb

# OR

wget -qO - https://apt.packages.shiftkey.dev/gpg.key | gpg --dearmor | sudo tee /usr/share/keyrings/shiftkey-packages.gpg > /dev/null
sudo sh -c 'echo "deb [arch=amd64] https://packagecloud.io/shiftkey/desktop/any/ any main" > /etc/apt/sources.list.d/packagecloud-shiftky-desktop.list'
sudo apt update && sudo apt install github-desktop