Use dotenvy instead of unmaintained dotenv and use it for the tests

src/main.rs

@@ -17,7 +17,6 @@ struct Args {
 }
 
 fn main() {
-    dotenv::dotenv().ok();
     env_logger::Builder::from_env(Env::default().default_filter_or("info")).init();
     let args = Args::parse();