Fix example

Author: roderickvd

discovery/examples/discovery.rs

@@ -1,4 +1,5 @@
 use futures::StreamExt;
+use librespot_core::SessionConfig;
 use librespot_discovery::DeviceType;
 use sha1::{Digest, Sha1};
 
@@ -7,7 +8,7 @@ async fn main() {
     let name = "Librespot";
     let device_id = hex::encode(Sha1::digest(name.as_bytes()));
 
-    let mut server = librespot_discovery::Discovery::builder(device_id)
+    let mut server = librespot_discovery::Discovery::builder(device_id, SessionConfig::default().client_id)
         .name(name)
         .device_type(DeviceType::Computer)
         .launch()