chore: rename ServiceName -> NamedService (#233)

BREAKING CHANGE: Rename `ServiceName` to `NamedService`.

interop/src/server.rs

@@ -7,7 +7,7 @@ use std::future::Future;
 use std::pin::Pin;
 use std::task::{Context, Poll};
 use std::time::Duration;
-use tonic::{body::BoxBody, transport::ServiceName, Code, Request, Response, Status};
+use tonic::{body::BoxBody, transport::NamedService, Code, Request, Response, Status};
 use tower::Service;
 
 pub use pb::test_service_server::TestServiceServer;
@@ -170,7 +170,7 @@ pub struct EchoHeadersSvc<S> {
     inner: S,
 }
 
-impl<S: ServiceName> ServiceName for EchoHeadersSvc<S> {
+impl<S: NamedService> NamedService for EchoHeadersSvc<S> {
     const NAME: &'static str = S::NAME;
 }