chore: update CHANGELOG.md

Author: GuillemGarciaDev

CHANGELOG.md

@@ -5,6 +5,12 @@ All notable changes to this project will be documented in this file.
 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).
 
+## [Unreleased]
+
+### Refactored
+
+- `TxResponse` `meta` field type changed to `TxMetadataBuilder`, enabling custom parsing for specific transactions metadata such as `Payment`, `NFTokenMint`, etc.
+
 ## [v0.1.13]
 
 ### Added