Prepare changelog for 3.4.3 (#316)

Author: Jean85

Diff for: CHANGELOG.md

@@ -5,7 +5,11 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/)
 and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.html).
 
 ## Unreleased
+ - ...
+
+## 3.4.3 (2020-02-03)
  - Change default of `in_app_include` to empty, due to getsentry/sentry-php#958 (#311)
+ - Improve class_alias robustness (#315)
 
 ## 3.4.2 (2020-01-29)
  - Remove space from classname used with `class_alias` (#313)