docs: typo

docs-en/05-develop/01-connect/03-go.md

@@ -47,7 +47,7 @@ import (
 )
 
 func main() {
-    dsn := os.Getenv("TDENGINE_CLOUD_TOKEN")
+    dsn := os.Getenv("TDENGINE_GO_DSN")
     taos, err := sql.Open("taosRestful", dsn)
     if err != nil {
         fmt.Println("failed to connect TDengine, err:", err)