修改 go 依赖代理

@@ -9,7 +9,7 @@ COPY ./go.sum go.sum
 COPY ./main.go main.go
 RUN ["ln","-sf","/usr/share/zoneinfo/Asia/Shanghai","/etc/localtime"]
 ENV GO111MODULE on
-ENV GOPROXY https://goproxy.io
+ENV GOPROXY https://goproxy.cn
 RUN ["go","mod","tidy"]
 RUN ["go","build"]
 RUN ["ls"]