style: format code

Author: hengfeiyang

README.md

@@ -7,8 +7,8 @@ use `.env` as config file and parse environments to config struct.
 ### derive EnvConfig
 
 ```rust
-use dotenvy::dotenv;
 use dotenv_config::EnvConfig;
+use dotenvy::dotenv;
 
 #[derive(Debug, EnvConfig)]
 struct Config {