docs: update README.md

README.md

@@ -195,8 +195,10 @@ Remove /Users/voidint/.g
   Due to the restricted access to the Golang official website in mainland China, it has become difficult to query and download go versions. Therefore, the environment variable `G_MIRROR` can be used to specify one or multiple mirror sites (separated by commas) from which g will query and download available go versions. The known available mirror sites are as follows:
 
   - Go official mirror site: https://golang.google.cn/dl/
-  - Go 语言中文网: https://studygolang.com/dl
-  - Aliyun open source mirror site: https://mirrors.aliyun.com/golang/
+  - Alibaba Cloud: https://mirrors.aliyun.com/golang/
+  - Nanjing University: https://mirrors.nju.edu.cn/golang/
+  - Huazhong University of Science and Technology: https://mirrors.hust.edu.cn/golang/
+  - University of Science and Technology of China: https://mirrors.ustc.edu.cn/golang/
 
 - What is the purpose of the environment variable `G_EXPERIMENTAL`?
 

README_CN.md

@@ -194,9 +194,11 @@ Remove /Users/voidint/.g
 
   由于中国大陆无法自由访问 Golang 官网，导致查询及下载 go 版本都变得困难，因此可以通过该环境变量指定一个或多个镜像站点（多个镜像站点之间使用英文逗号分隔），g 将从该站点查询、下载可用的 go 版本。已知的可用镜像站点如下：
 
-  - Go 官方镜像站点：https://golang.google.cn/dl/
-  - Go 语言中文网：https://studygolang.com/dl
-  - 阿里云开源镜像站点：https://mirrors.aliyun.com/golang/
+  - Go 官方镜像站：https://golang.google.cn/dl/
+  - 阿里云开源镜像站：https://mirrors.aliyun.com/golang/
+  - 南京大学开源镜像站：https://mirrors.nju.edu.cn/golang/
+  - 华中科技大学开源镜像站：https://mirrors.hust.edu.cn/golang/
+  - 中国科学技术大学开源镜像站：https://mirrors.ustc.edu.cn/golang/
 
 - 环境变量`G_EXPERIMENTAL`有什么作用？