Update changelog

Author: compojoom

CHANGELOG.md

@@ -6,6 +6,12 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/).
 
 ## [Unreleased]
 
+## [0.15.1] - 2021-09-29
+
+### Fixed
+
+- Trustline update requests with transfer set to "0" were calling the wrong contract function
+
 ## [0.15.0] - 2021-05-04
 
 ### Added