Update CHANGELOG.md

Author: localden

CHANGELOG.md

@@ -7,7 +7,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [0.0.12] - 2025-09-21
 
-### Fixed
+### Changed
 
 - Added additional context for OpenAI Codex users - they need to set an additional environment variable, as described in [#417](https://github.com/github/spec-kit/issues/417).