update changelog

CHANGELOG.md

@@ -15,8 +15,10 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 - Display external payment ID on payments details page [#59](https://github.com/stellar/stellar-disbursement-platform-frontend/pull/59)
 - Add a cancel button to payments details page [#60](https://github.com/stellar/stellar-disbursement-platform-frontend/pull/60)
 - Add env variable injection to dashboard [#62](https://github.com/stellar/stellar-disbursement-platform-frontend/pull/62)
+- Add SMS preview & editing before sending a new disbursement [#66](https://github.com/stellar/stellar-disbursement-platform-frontend/pull/66)
 - Display `Created By` and `Started By` on disbursement details page [#68](https://github.com/stellar/stellar-disbursement-platform-frontend/pull/68)
 
+
 ### Changed
 
 - State Refactors