Add CHANGELOG entry

Author: coolreader18

CHANGELOG.md

@@ -30,6 +30,8 @@ This project adheres to [Semantic Versioning](https://semver.org/).
   `sys::kevent::Kqueue::kevent`, and `sys::event::kqueue` is deprecated in
   favor of `sys::kevent::Kqueue::new`.
   ([#1943](https://github.com/nix-rust/nix/pull/1943))
+- `nix::socket` and `nix::select` are now available on Redox.
+  ([#2012](https://github.com/nix-rust/nix/pull/2012))
 
 ### Fixed
 - Fix `SockaddrIn6` bug that was swapping flowinfo and scope_id byte ordering.