Update changelog

Author: oblique

CHANGELOG.md

@@ -5,6 +5,14 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## Unreleased
+
+### Improve
+
+- Rewrite `tftpd-targz.rs` example with `aysnc-tar` and `async-compression`
+  crates.
+- Use only `alloc` feature flag for `futures-util`.
+
 ## [0.3.0] - 2020-08-17
 
 ### Added