Updated changelog

Author: rozbb

rand_chacha/CHANGELOG.md

@@ -4,6 +4,9 @@ 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).
 
+## [Unreleased]
+- Made `rand_chacha` propagate the `std` and `getrandom` features down to `rand_core`
+
 ## [0.3.1] - 2021-06-09
 - add getters corresponding to existing setters: `get_seed`, `get_stream` (#1124)
 - add serde support, gated by the `serde1` feature (#1124)