chore: add changelog entry

Author: hmalik88

packages/keyring-api/CHANGELOG.md

@@ -7,6 +7,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Added
+
+- Add `TransactionType.Approve` for token approval transactions ([#537](https://github.com/MetaMask/accounts/pull/537))
+
 ## [23.0.1]
 
 ### Fixed