Update changelog for Rename selection --> brushSelection, #1423

Author: kum-deepak

Changelog.md

@@ -1,6 +1,7 @@
 ## 3.0.0 beta 1
 * First NPM release of dc.js, compatible with D3 versions 4 and 5. Thanks to Deepak Kumar for all his effort on the port! We've made every effort to keep the library backward-compatible, but see [the 3.0 changes in the wiki](https://github.com/dc-js/dc.js/wiki/Changes-in-dc.js-version-3.0).
 * `fadeDeselectedArea` checks if brushing is enabled for the chart. Restores backward compatibility. By Deepak Kumar. ([#1422](https://github.com/dc-js/dc.js/pull/1422) / [#1401](https://github.com/dc-js/dc.js/issues/1401))
+* Rename `selection` --> `brushSelection`. By Deepak Kumar.([#1423](https://github.com/dc-js/dc.js/issues/1423) / [#1398](https://github.com/dc-js/dc.js/issues/1398))
 
 ## 3.0.0 alpha 12
 * Use `d3.stack` from d3v4+, transforming the data from/to the old layer/stack objects. Remove `d3v3-compat.js` ([#1375](https://github.com/dc-js/dc.js/issues/1375)