Forward-port v1.9.1 changelog

Signed-off-by: Christoph Wurst <christoph@winzerhof-wurst.at>

CHANGELOG.md

@@ -1,6 +1,10 @@
 # Changelog
 All notable changes to this project will be documented in this file.
 
+## 1.9.1 - 2021-03-03
+### Fixed
+- Missing route for attachments zip response
+
 ## 1.9.0 - 2021-03-03
 ### Added
 - Sieve filter editor