Update transports/tcp/CHANGELOG.md

Co-authored-by: Akihito Nakano <sora.akatsuki@gmail.com>

Author: jxs

transports/tcp/CHANGELOG.md

@@ -1,6 +1,6 @@
 ## 0.44.1
 - Expose `socket2`'s `set_linger` config option.
-  See [PR XXXX](https://github.com/libp2p/rust-libp2p/pull/5955)
+  See [PR 6225](https://github.com/libp2p/rust-libp2p/pull/5955)
 
 ## 0.44.0