Update CHANGELOG.md

Author: alexcjohnson

Diff for: CHANGELOG.md

@@ -4,7 +4,7 @@ This project adheres to [Semantic Versioning](http://semver.org/).
 
 ## UNRELEASED
 ### Fixed
-- [#179](https://github.com/plotly/dash-html-components/pull/178) - Fixes [#77](https://github.com/plotly/dash-html-components/issues/77) Added `allow` and `refferrerPolicy` properties to `html.Iframe`
+- [#179](https://github.com/plotly/dash-html-components/pull/178) - Fixes [#77](https://github.com/plotly/dash-html-components/issues/77) Added `allow` and `referrerPolicy` properties to `html.Iframe`
 
 - [#178](https://github.com/plotly/dash-html-components/pull/178) - Fix [#161](https://github.com/plotly/dash-html-components/issues/161) <object> `data` property, and fix [#129](https://github.com/plotly/dash-html-components/issues/129) obsolete, deprecated, and discouraged elements. No elements were removed, but comments were added to the documentation about these elements detailing their limitations.