rand_core: update CHANGELOG for 0.6.4 (#1253)

Author: dhardy

rand_core/CHANGELOG.md

@@ -4,9 +4,10 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/)
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
-## [0.6.4] - 2021-08-20
-### Fixed
+## [0.6.4] - 2022-09-15
 - Fix unsoundness in `<BlockRng64 as RngCore>::next_u32` (#1160)
+- Reduce use of `unsafe` and improve gen_bytes performance (#1180)
+- Add `CryptoRngCore` trait (#1187, #1230)
 
 ## [0.6.3] - 2021-06-15
 ### Changed