Update CHANGELOG for version 1.2.2

Updated the unreleased section to reflect version 1.2.2 and added a fixed entry for RSS in the default theme.

Author: thiagogq

CHANGELOG.md

@@ -5,7 +5,11 @@ 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).
 
-## [Unreleased]
+## [Unreleased - 1.2.2]
+
+### Fixed
+
+- RSS in the default theme.
 
 ## [1.2.1]