Update CHANGELOG.md

Author: LiamConnors

CHANGELOG.md

@@ -4,6 +4,18 @@ This project adheres to [Semantic Versioning](http://semver.org/).
 
 ## [UNRELEASED]
 
+### Updated
+  - Updated Plotly.js from version 2.20.0 to version 2.23.0. See the [plotly.js CHANGELOG](https://github.com/plotly/plotly.js/blob/master/CHANGELOG.md#2230----2023-05-12) for more information. Notable changes include:
+    - Add `texttemplate` to shape.label for parametric shapes i.e. line, rect and circle [[#6527](https://github.com/plotly/plotly.js/pull/6527)],
+   with thanks to the [Volkswagen](https://www.volkswagenag.com) Center of Excellence for Battery Systems for sponsoring development!
+    - Add strict option to custom bundle command [[#6557](https://github.com/plotly/plotly.js/pull/6557)],
+   with thanks to @CallumNZ for the contribution!
+    - Add `legend` references to traces and `legend2`, `legend3`, etc. to layout,
+   also add `visible` to legend i.e. to allow positioning multiple legends on a graph [[#6535](https://github.com/plotly/plotly.js/pull/6535)],
+   this feature was anonymously sponsored: thank you to our sponsor!
+    - Add `legend.xref` and `legend.yref` to enable container-referenced positioning of legends [[#6589](https://github.com/plotly/plotly.js/pull/6589)], with thanks to [Gamma Technologies](https://www.gtisoft.com/) for sponsoring the related development.
+    - Add `colorbar.xref` and `colorbar.yref` to enable container-referenced positioning of colorbars [[#6593](https://github.com/plotly/plotly.js/pull/6593)], with thanks to [Gamma Technologies](https://www.gtisoft.com/) for sponsoring the related development.
+
 ### Fixed
   - Fixed another compatibility issue with Pandas 2.0, just affecting `px.*(line_close=True)` [[#4190](https://github.com/plotly/plotly.py/pull/4190)]
   - Added some rounding to the `make_subplots` function to handle situations where the user-input specs cause the domain to exceed 1 by small amounts [[#4153](https://github.com/plotly/plotly.py/pull/4153)]