update changelog

Author: beakerandjake

CHANGELOG.md

@@ -6,6 +6,8 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 ## [Unreleased]
+### Fixed
+- Fixed issue with puzzle unlock time being 2pm EST instead of midnight EST ([#238](https://github.com/beakerandjake/advent-of-code-runner/issues/238))
 
 ## [1.6.0] - 2023-11-17
 ### Changed