chore: Fix clippy lints (#950)

Author: tottoto

tonic-build/src/prost.rs

@@ -388,7 +388,7 @@ impl Builder {
             PathBuf::from(std::env::var("OUT_DIR").unwrap())
         };
 
-        config.out_dir(out_dir.clone());
+        config.out_dir(out_dir);
         if let Some(path) = self.file_descriptor_set_path.as_ref() {
             config.file_descriptor_set_path(path);
         }

tonic/src/service/interceptor.rs

@@ -169,7 +169,7 @@ where
         // HTTP method of the HTTP request, so we extract them here and then add them back in below.
         let uri = req.uri().clone();
         let method = req.method().clone();
-        let version = req.version().clone();
+        let version = req.version();
         let req = crate::Request::from_http(req);
         let (metadata, extensions, msg) = req.into_parts();
 

tonic/src/transport/server/conn.rs

@@ -116,10 +116,7 @@ where
         let inner = inner.connect_info();
 
         let certs = if let Some(certs) = session.peer_certificates() {
-            let certs = certs
-                .into_iter()
-                .map(|c| Certificate::from_pem(c))
-                .collect();
+            let certs = certs.iter().map(Certificate::from_pem).collect();
             Some(Arc::new(certs))
         } else {
             None

tonic/src/transport/server/mod.rs

@@ -151,7 +151,6 @@ impl<L> Server<L> {
     /// Configure TLS for this server.
     #[cfg(feature = "tls")]
     #[cfg_attr(docsrs, doc(cfg(feature = "tls")))]
-    #[must_use]
     pub fn tls_config(self, tls_config: ServerTlsConfig) -> Result<Self, Error> {
         Ok(Server {
             tls: Some(tls_config.tls_acceptor().map_err(Error::from_source)?),