chore: prepare v1.2.1 (#137)

Signed-off-by: Francesco Noacco <francesco.noacco@secomind.com>

Author: noaccOS

CHANGELOG.md

@@ -4,7 +4,7 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/)
 and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.html).
 
-## [1.2.1] - Unreleased
+## [1.2.1] - 2026-03-06
 
 ### Fixed
 - [astarte_realm_management] Insufficient validation for conflicting options in interface aggregate mappings