docs(readme): update recommend server frameworks (#3232)

Suggest Axum first, and mention that warp uses a functional paradigm.

Closes #3222

README.md

@@ -27,8 +27,8 @@ hyper is a relatively low-level library, meant to be a building block for
 libraries and applications.
 
 If you are looking for a convenient HTTP client, then you may wish to consider
-[reqwest](https://github.com/seanmonstar/reqwest). If you are looking for a
-convenient HTTP server, then you may wish to consider [warp](https://github.com/seanmonstar/warp).
+[reqwest](https://github.com/seanmonstar/reqwest).
+If you are not sure what HTTP server to choose, then you may want to consider [axum](https://github.com/tokio-rs/axum) or [warp](https://github.com/seanmonstar/warp), the latter taking a more functional approach.
 Both are built on top of this library.
 
 ## Contributing