feat(quic): deprecate QUIC draft-29 version support

transports/quic/CHANGELOG.md

@@ -2,6 +2,9 @@
 
 <!-- Update to libp2p-core v0.43.0 -->
 
+- Deprecate `Config::support_draft_29`.
+  See [PR 5786](https://github.com/libp2p/rust-libp2p/pull/5786).
+
 ## 0.11.1
 
 - Update `libp2p-tls` to version `0.5.0`, see [PR 5547]

transports/quic/src/config.rs

@@ -59,6 +59,8 @@
     /// If support for draft-29 is enabled servers support draft-29 and version 1 on all
     /// QUIC listening addresses.
     /// As client the version is chosen based on the remote's address.
+    #[expect(deprecated)]
+    #[deprecated(note = "QUIC draft versions are no longer supported")]
     pub support_draft_29: bool,
 
     /// TLS client config for the inner [`quinn::ClientConfig`].
@@ -85,7 +87,8 @@
         Self {
             client_tls_config,
             server_tls_config,
+            #[expect(deprecated)]
             support_draft_29: false,
             handshake_timeout: Duration::from_secs(5),
             max_idle_timeout: 10 * 1000,
             max_concurrent_stream_limit: 256,
@@ -132,7 +135,8 @@
             keep_alive_interval,
             max_connection_data,
             max_stream_data,
+            #[expect(deprecated)]
             support_draft_29,
             handshake_timeout: _,
             keypair,
             mtu_discovery_config,
@@ -169,6 +173,7 @@
             })
             .unwrap_or_default();
 
+        #[expect(deprecated)]
         if !support_draft_29 {
             endpoint_config.supported_versions(vec![1]);
         }