Update changelog for version 3.4.1 and add namespace selection feature in iop command

Author: grongierisc

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/spec/v2.0.0.html).
 
-## [Unreleased]
+## [3.4.1] - 2025-04-30
 
 ### Added
 - Add namespace selection in the `iop` command