CodeMirror 6.0 migration: update changelog

Author: NomarCub

CHANGELOG.md

@@ -5,6 +5,12 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+# [1.12.1]
+
+### Fixed
+
+- Migrated to CodeMirror 6.0 required in Obsidian v0.15.
+
 # [1.12.0]
 
 ### Added