feat(yamux): rename symbols to follow module-based naming convention

Implements our naming convention for the `libp2p-yamux` crate.

Related: #2217.

Pull-Request: #3852.

swarm/src/lib.rs

@@ -2067,7 +2067,7 @@ mod tests {
             .authenticate(plaintext::PlainText2Config {
                 local_public_key: local_public_key.clone(),
             })
-            .multiplex(yamux::YamuxConfig::default())
+            .multiplex(yamux::Config::default())
             .boxed();
         let behaviour = CallTraceBehaviour::new(MockBehaviour::new(handler_proto));
         match ThreadPool::new().ok() {