Bump version to 17.6.0 and add payment API fields

Updated version number to 17.6.0 and added new fields for payment API.

Author: tl-tai-tang

CHANGELOG.md

@@ -5,7 +5,7 @@ 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/).
 
-## [17.5.2] - 2026-05-15
+## [17.6.0] - 2026-05-15
 ### Added
 * * Add support for `user_interaction` and `use_cases` fields in payment API for commercial mandate