解决方案
修改`/etc/apt/sources.list.d/raspi.list`
deb http://mirrors.tuna.tsinghua.edu.cn/raspberry-pi-os/raspbian/ buster main non-free contrib rpi
deb-src http://mirrors.tuna.tsinghua.edu.cn/raspberry-pi-os/raspbian/ buster main non-free contrib rpi
修改之后更新`sudo apt update`