Add display width change to CHANGELOG.md

Author: jonmmease

CHANGELOG.md

@@ -7,6 +7,9 @@ This project adheres to [Semantic Versioning](http://semver.org/).
  - Added suport for using JupyterDash in Google Colab ([#27](https://github.com/plotly/jupyter-dash/pull/27))
  - Added support for installing JupyterDash from git using pip: (e.g. `pip install git+https://github.com/plotly/jupyter-dash.git@master`)
 
+### Changed
+ - The default display width in `mode='inline'` is now `100%` to fill the screen width. 
+
 ## 0.2.1 - 2020-05-19
 ### Added
  - Remove f-strings to support Python 3.5