should go into a minor changelog

Author: nicolaskruchten

CHANGELOG.md

@@ -2,16 +2,18 @@
 All notable changes to this project will be documented in this file.
 This project adheres to [Semantic Versioning](http://semver.org/).
 
+## [4.9.0] - unreleased
+
+### Updated
+
+- `plotly.express.imshow` now uses data frame index names and values to populate axis parameters by default ([#2539](https://github.com/plotly/plotly.py/pull/2539))
+
 ## [4.8.2] - unreleased
 
 ### Fixed
 
 - Fixed special cases with `px.sunburst` and `px.treemap` with `path` input ([#2524](https://github.com/plotly/plotly.py/pull/2524))
 
-### Updated
-
-- `plotly.express.imshow` now uses data frame index names and values to populate axis parameters by default ([#2539](https://github.com/plotly/plotly.py/pull/2539))
-
 ## [4.8.1] - 2020-05-28
 
 ### Fixed