docs: updated tiny example in readme

Author: arctic-hen7

README.md

@@ -26,7 +26,7 @@ Here's a taste of Perseus (see [the _tiny_ example](https://github.com/arctic-he
 use perseus::{Html, PerseusApp, Template};
 use sycamore::view;
 
-#[perseus::main]
+#[perseus::main(perseus_warp::dflt_server)]
 pub fn main<G: Html>() -> PerseusApp<G> {
     PerseusApp::new().template(|| {
         Template::new("index").template(|cx, _| {