chore: update changelog

Author: Skn0tt

CHANGELOG.md

@@ -2,6 +2,9 @@
 All notable changes to this project will be documented in this file.
 This project adheres to [Semantic Versioning](http://semver.org/).
 
+### Fixed
+  - Fixed non-determinism in `to_html` function, resulting in unneccessary checksum differences [#3449](https://github.com/plotly/plotly.py/issues/3449)
+
 ## [5.4.0] - 2021-11-15
 
 ### Fixed