Add changelog entry for #340

Author: Jean85

CHANGELOG.md

@@ -5,6 +5,7 @@ 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
+ - Capture multiple events if multiple exceptions are generated in a Messenger Worker context (#340, thanks to @emarref)
  - ...
 
 ## 3.5.0 (2020-05-04)