Update changelog

Author: vearutop

CHANGELOG.md

@@ -4,7 +4,10 @@ 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]
+## [0.2.20] - 2019-10-02
+
+### Fixed
+- Missing return and argument phpdoc types for `array` and `mixed`.
 
 ## [0.2.19] - 2019-10-02
 
@@ -16,6 +19,6 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Fixed
 - Description trimming bug.
 
-[Unreleased]: https://github.com/swaggest/php-code-builder/compare/v0.2.19...HEAD
+[0.2.20]: https://github.com/swaggest/php-code-builder/compare/v0.2.19...v0.2.20
 [0.2.19]: https://github.com/swaggest/php-code-builder/compare/v0.2.18...v0.2.19
 [0.2.18]: https://github.com/swaggest/php-code-builder/compare/v0.2.17...v0.2.18