Write changelog

Author: sue445

CHANGELOG.md

@@ -1,5 +1,10 @@
 ## [Unreleased]
-[full changelog](http://github.com/ruby-go-gem/ruby_header_parser/compare/v0.3.0...main)
+[full changelog](http://github.com/ruby-go-gem/ruby_header_parser/compare/v0.3.1...main)
+
+## [0.3.1](https://github.com/ruby-go-gem/ruby_header_parser/releases/tag/v0.3.1) - 2024-12-15
+[full changelog](http://github.com/ruby-go-gem/ruby_header_parser/compare/v0.3.0...v0.3.1)
+
+* Change arg of `rb_gc_register_address` and `rb_gc_unregister_address` to in_ref https://github.com/ruby-go-gem/ruby_header_parser/pull/24
 
 ## [0.3.0](https://github.com/ruby-go-gem/ruby_header_parser/releases/tag/v0.3.0) - 2024-11-24
 [full changelog](http://github.com/ruby-go-gem/ruby_header_parser/compare/v0.2.0...v0.3.0)