Update CHANGELOG.md for version 3.5.5 release and document new features

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]
+## [3.5.5] - 2026-01-23
 ### Added
 - Add `iop --update` command to update a production from the command line
 - New info displayed in `iop --help` command showing current namespace