generate 2.1.2 changelog

Author: mmoll

CHANGELOG.md

@@ -3,6 +3,10 @@
 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).
 
+## [2.1.2] - 2018-09-06
+### Changed
+- prefer builtin-functions for performance
+
 ## [2.1.1] - 2018-05-17
 ### Changed
 - Check for empty needle when calling strpos, fixes #78