Feature: Add goctl env (#1557)

tools/goctl/pkg/golang/install.go

@@ -0,0 +1,17 @@
+package golang
+
+import (
+	"os"
+	"os/exec"
+)
+
+func Install(git string) error {
+	cmd := exec.Command("go", "install", git)
+	env := os.Environ()
+	env = append(env, "GO111MODULE=on", "GOPROXY=https://goproxy.cn,direct")
+	cmd.Env = env
+	cmd.Stdout = os.Stdout
+	cmd.Stderr = os.Stderr
+	err := cmd.Run()
+	return err
+}