Prepare v0.2.1 release

Author: andrewkroh

CHANGELOG.md

@@ -2,19 +2,13 @@
 All notable changes to this project will be documented in this file.
 This project adheres to [Semantic Versioning](http://semver.org/).
 
-## [Unreleased]
+## [0.2.1]
 
 ### Added
 
 - Added better error messages for when `NewAuditClient` fails due to the
   Linux kernel not supporting auditing (CONFIG_AUDIT=n). #32
 
-### Changed
-
-### Deprecated
-
-### Removed
-
 ## [0.2.0]
 
 ### Changed