Changelog: UB fix in correct version

Layout related UB was fixed in 0.3.16 but it was reported in 0.4.0 which would lead people to believe they have broken dependency even if they don't.
Moving it to appropriate version avoids confusion.

Author: Kixunil

CHANGELOG.md

@@ -169,7 +169,6 @@
 * Use correct inmutable references in `Socket::send_with_flags` and
   `Socket::send_out_of_band`.
 * Use `IPPROTO_IPV6` in `Socket::join_multicast_v6` on Windows.
-* Don't assume the memory layout of `std::net::SocketAddr`.
 * Use `c_int` instead of `i32` where appropriate.
 
 ## From v0.4.0-alpha.1 to v0.4.0-alpha.2
@@ -190,3 +189,8 @@
 ## From v0.4.0-alpha.5 to v0.4.0
 
 * Use `SO_LINGER_SEC` on macOS for `Socket::get/set_linger`.
+
+# 0.3.16
+
+* Don't assume the memory layout of `std::net::SocketAddr`.
+* Other changes omited