Prepare changelog for 3.5

Author: Jean85

Diff for: CHANGELOG.md

@@ -5,10 +5,12 @@ 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
+ - ...
+
+## 3.5.0 (2020-05-04)
  - Capture and flush messages in a Messenger Worker context (#326, thanks to @emarref)
  - Support Composer 2 (#335)
  - Avoid issues with dependency lower bound, fix #331 (#335)
- - ...
 
 ## 3.4.4 (2020-03-16)
  - Improve `release` option default value (#325)