Adding changelog for key API and Documentation updates

Author: nlfoster

CHANGELOG.md

@@ -3,7 +3,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 ## Documentation Update <sub><sup>(February 5, 2021)</sup></sub>
-### Added
+### Changed
 * Updated code examples to use modern practices.
 * `var` has been replaced with `const` or `let`, and all functions have been replaced by arrow functions.