Update Change Log

Author: MarkBaker

CHANGELOG.md

@@ -96,6 +96,7 @@ and this project adheres to [Semantic Versioning](https://semver.org).
 - Handle booleans in conditional styles properly [PR #2654](https://github.com/PHPOffice/PhpSpreadsheet/pull/2654)
 - Fix for reading files in the root directory of a ZipFile, which should not be prefixed by relative paths ("./") as dirname($filename) does by default. 
 - Fix invalid style of cells in empty columns with columnDimensions and rows with rowDimensions in added external sheet. [PR #2739](https://github.com/PHPOffice/PhpSpreadsheet/pull/2739)
+- Time Interval Formatting [Issue #2768](https://github.com/PHPOffice/PhpSpreadsheet/issues/2768) [PR #2772](https://github.com/PHPOffice/PhpSpreadsheet/pull/2772)
 
 ## 1.22.0 - 2022-02-18