Use keepachangelog.com format

CHANGELOG.md

@@ -1,11 +1,22 @@
-### v0.2.0
+# Changelog
+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]
+
+## [v0.2.0] - 2020-04-06
+### Added
+- added copyright headers
+- improved error handling
+
+### Changed
  - switched from oping to tokio-ping. This removes the dependency on liboping and
    a bunch of custom build tooling.
- - improved error handling
- - added copyright headers
  - update dependencies
  - use async/await syntax and updated async ecosystem libraries where possible
 
-### v0.1.0
+## [v0.1.0] - 2019-02-06
 Initial implementation. This works, but still has compiler warnings during
 compilation.