升级安装go1.13.5

运行文件时报错 verifying github.com/mattn/go-isatty@v0.0.10-0.20190818123653-bf9a1dea1961/go.mod: github.com/mattn/go-isatty@v0.0.10-0.20190818123653-bf9a1dea1961/go.mod: Get https://sum.golang.org/lookup/github.com/mattn/go-isatty@v0.0.10-0.20190818123653-bf9a1dea1961: dial tcp 216.58.200.49:443: connectex: A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond.
verifying github.com/onsi/gomega@v1.8.1/go.mod: github.com/onsi/gomega@v1.8.1/go.mod: Get https://sum.golang.org/lookup/github.com/onsi/gomega@v1.8.1: dial tcp 216.58.200.49:443: connectex: A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond.
verifying github.com/mattn/go-colorable@v0.1.3-0.20190818022642-388941e3ea99/go.mod: github.com/mattn/go-colorable@v0.1.3-0.20190818022642-388941e3ea99/go.mod: Get https://sum.golang.org/lookup/github.com/mattn/go-colorable@v0.1.3-0.20190818022642-388941e3ea99: dial tcp 216.58.200.49:443: connectex: A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond.

在Go 1.13中，我们可以通过GOPROXY来控制代理

注意 ： 通过 GOPRIVATE 控制私有库不走代理

这个网站是被墙了的，用于验证包的有效性，可以通过如下命令关闭：

go env -w GOSUMDB=off

私有仓库自动忽略验证

可以设置 go env -w GOSUMDB="sum.golang.google.cn"， 这个是专门为国内提供的sum 验证服务