Prepare 2.2.0 release

Author: adriansr

CHANGELOG.md

@@ -7,16 +7,22 @@ This project adheres to [Semantic Versioning](http://semver.org/).
 
 ### Added
 
-- Add user and group mapping for ECS 1.8 compatibility [#86](https://github.com/elastic/go-libaudit/pull/86)
-
 ### Changed
 
-- Change ECS category of USER_START and USER_END messages to `session`. [#86](https://github.com/elastic/go-libaudit/pull/86)
-
 ### Removed
 
 ### Deprecated
 
+## [2.2.0]
+
+### Added
+
+- Add user and group mapping for ECS 1.8 compatibility [#86](https://github.com/elastic/go-libaudit/pull/86)
+
+### Changed
+
+- Change ECS category of USER_START and USER_END messages to `session`. [#86](https://github.com/elastic/go-libaudit/pull/86)
+
 ## [2.1.0]
 
 ### Added