Update Changelog for previous commit

Author: PowerKiKi

CHANGELOG.md

@@ -20,6 +20,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 - `Helper\Html` support UTF-8 HTML input - [#444](https://github.com/PHPOffice/PhpSpreadsheet/issues/444)
 - Xlsx loaded an extra empty comment for each real comment - [#375](https://github.com/PHPOffice/PhpSpreadsheet/issues/375)
 - Xlsx reader do not read rows and columns filtered out in readFilter at all - [#370](https://github.com/PHPOffice/PhpSpreadsheet/issues/370)
+- Make newer Excel versions properly recalculate formulas on document open - [#456](https://github.com/PHPOffice/PhpSpreadsheet/issues/456)
 
 ## [1.2.1] - 2018-04-10