Add CHANGELOG

Author: benglewis

src/lightning/pytorch/CHANGELOG.md

@@ -4,6 +4,8 @@ All notable changes to this project will be documented in this file.
 
 The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/).
 
+- Added a new `checkpoint_artifact_path_prefix` parameter to the MLflow logger which can control the path to where the MLflow artifacts for the model checkpoints are stored.
+
 ## [2.5.0] - 2024-12-19
 
 ### Added