apt-get update fails with public key errors apt-get update 失败，出现公钥错误93D6889F9F0E78D5
解决方法：
sudo wget https://apt.armbian.com/armbian.key -O key sudo gpg --dearmor < key | sudo tee /usr/share/keyrings/armbian.gpg > /dev/null sudo chmod go+r /usr/share/keyrings/armbian.gpg sudo echo "deb [arch=$(dpkg --print-architecture) signed-by=/usr/share/keyrings/armbian.gpg] http://apt.armbian.com $(lsb_release -cs) main $(lsb_release -cs)-utils $(lsb_release -cs)-desktop" | sudo tee /etc/apt/sources.list.d/armbian.list apt update
