update tense of changelog

Author: chriddyp

CHANGELOG.md

@@ -5,7 +5,7 @@ This project adheres to [Semantic Versioning](http://semver.org/).
 ## [Unreleased]
 ### Added
 - offline embedded plots are now responsive to window resizing when `output_type == "div"` is set in `plotly.offline.iplot()`.
-- Beta: Methods were added that wrap the API endpoint for managing Dash objects on plot.ly. The API interface is under `plotly.api.v2.dash_apps`
+- Beta: Added API methods that wrap the API endpoint for managing Dash objects on plot.ly. The API interface is under `plotly.api.v2.dash_apps`
 
 ## [2.0.7] - 2017-04-07
 ### Updated