✏️ update changelog

Author: erincdustin

CHANGELOG.md

@@ -5,6 +5,11 @@ All notable changes to the ordercloud-javascript-sdk will be documented in this
 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).
 
+## [4.8.8] - 2022-05-19
+### Added
+- SDK up to date with [API v1.0.238](https://ordercloud.io/release-notes/v1.0.238)
+- Introduces Order Returns and adds Message Sender templates
+- PriceScheduleID added to LineItems
 ## [4.7.8] - 2022-05-04
 ### Added
 - Added an optional `customRoles` array to the authentication methods to support authenticating with custom roles, in addition to standard ApiRoles.