Update CHANGELOG

Author: rachelekm

CHANGELOG.md

@@ -53,6 +53,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 - Add client feedback copy updates [#793](https://github.com/azavea/echo-locator/pull/793)
 - Add transit routing architecture ADR [#804](https://github.com/azavea/echo-locator/pull/804)
 - Add neighborhood csv submission instructions [#801](https://github.com/azavea/echo-locator/pull/801)
+- Add Spanish and Mandarin translations [#807](https://github.com/azavea/echo-locator/pull/807)
 
 ### Changed