https://github.com/protocolbuffers/protobuf/releases/tag/v3.15.2
windows 下载 https://github.com/protocolbuffers/protobuf/releases/download/v3.15.2/protoc-3.15.2-win64.zip
解压后把protoc.exe复制到gopath的bin目录下，或者新建目录加入环境变量
D:\www\go\greet>protoc --version
libprotoc 3.15.1
原文：https://www.cnblogs.com/brady-wang/p/14440969.html