新版rust使用镜像源配置写法

配置文件为//.cargo/config文件
格式如下

[registries]
ustc-registry = { index = "https://mirrors.ustc.edu.cn/crates.io-index/" }
[source.crates-io]
replace-with = 'ustc'
[source.ustc]
registry = "https://mirrors.ustc.edu.cn/crates.io-index/"

参考官网地址 链接 https://doc.rust-lang.org/cargo/reference/registries.html