Update CHANGELOG for 4.3.0

Author: jonmmease

CHANGELOG.md

@@ -2,6 +2,22 @@
 All notable changes to this project will be documented in this file.
 This project adheres to [Semantic Versioning](http://semver.org/).
 
+## [4.3.0] - 2019-11-11
+
+### Updated
+ - Updated Plotly.js to version 1.51.1. See the
+ [plotly.js CHANGELOG](https://github.com/plotly/plotly.js/blob/master/CHANGELOG.md#1511----2019-11-04)
+ for more information
+ - Improved propagation of empty templates ([#1892](https://github.com/plotly/plotly.py/pull/1892))
+ - Update the `add_annotations`/`add_shapes`/`add_images` methods to no longer default to adding objects in paper coordinates. This allows plotly.js to determine the default reference frame based on context ([#1888](https://github.com/plotly/plotly.py/pull/1888))
+ - Use the default template's background color for displaying color swatches ([#1872](https://github.com/plotly/plotly.py/pull/1872)). Special thanks to [@joelostblom](https://github.com/joelostblom) for this contribution!
+ 
+### Added
+ - Added image trace type ([plotly.js#4289](https://github.com/plotly/plotly.js/pull/4289), [plotly.js#4307](https://github.com/plotly/plotly.js/pull/4307), [plotly.js#4313](https://github.com/plotly/plotly.js/pull/4313), [plotly.js#4319](https://github.com/plotly/plotly.js/pull/4319))
+ - Added matplotlib-style `plotly.express.imshow` convenience function to display images and heatmaps ([#1855](https://github.com/plotly/plotly.py/pull/1855), [#1885](https://github.com/plotly/plotly.py/pull/1885))
+ - Added matplotlib-style `simple_white` template ([#1864](https://github.com/plotly/plotly.py/pull/1864))
+ - Added support for using an externally managed orca server for image export features ([#1850](https://github.com/plotly/plotly.py/pull/1850)). Special thanks to [@miriad](https://github.com/miriad) for this contribution.
+
 ## [4.2.1] - 2019-10-18
 ### Fixed
  - Fixed regression in 4.2.0 that caused all figure factories to require that scikit-image be installed ([#1832](https://github.com/plotly/plotly.py/pull/1832))