update: add changelog

CHANGELOG.md

@@ -6,4 +6,21 @@ Check [Keep a Changelog](http://keepachangelog.com/) for recommendations on how
 
 ## [Unreleased]
 
-- Initial release
+## [0.1.0] - 2024-12-13
+
+### Added
+
+- Support for highlighting `mass`, `width`, `pdg`, `color`, and other particle attributes as `keyword.property.lhp`.
+- Added grammar rules for `anti`, `gamma`, `gamma5`, and other LanHEP-specific predefined terms.
+
+### Fixed
+
+- Improved particle name detection for cases with quoted identifiers.
+
+## [0.0.1] - 2024-12-12
+
+### Added
+
+- Initial release with syntax highlighting for LanHEP language.
+- Support for comments (`%`), brackets (`{}`, `()`), and strings.
+- Basic particle and attribute highlighting.