debian 设置镜像源
在 /etc/apt/sources.list 下将原来的内容删去，然后改为如下内容(清华镜像源)
deb https://mirrors.tuna.tsinghua.edu.cn/debian/ bookworm main contrib non-free non-free-firmware
deb-src https://mirrors.tuna.tsinghua.edu.cn/debian/ bookworm main contrib non-free non-free-firmware