example-service: set max frame length to usize::MAX

I don't know what the intention was behind using u32::MAX + 1 but since the
argument's type is usize this is the only giant value that makes sense to me.

example-service/src/client.rs

@@ -43,7 +43,7 @@ async fn main() -> io::Result<()> {
     let name = flags.value_of("name").unwrap().into();
 
     let mut transport = tarpc::serde_transport::tcp::connect(server_addr, Json::default);
-    transport.config_mut().max_frame_length(4294967296);
+    transport.config_mut().max_frame_length(usize::MAX);
 
     // WorldClient is generated by the service attribute. It has a constructor `new` that takes a
     // config and any Transport as input.