docs: update CHANGELOG

Author: StrangeRanger

hardening/SSHD Hardening/CHANGELOG.md

@@ -4,6 +4,12 @@ All notable changes to this project will be documented in this file.
 
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/), and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## v2.2.0 - 2025-11-02
+
+### Added
+
+- MaxStartups is configured to `10:30:60`. This limits concurrent unauthenticated connections to mitigate DoS attacks.
+
 ## v2.1.0 - 2025-08-09
 
 ### Added