Changelog for missing Python param defaults

Author: kieran-ryan

CHANGELOG.md

@@ -11,6 +11,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 
 ### Fixed
 - Removed repeated 'the' from error message for use of alternations inside optionals ([#252](https://github.com/cucumber/cucumber-expressions/issues/252))
+- [Python] Missing keyword argument defaults in parameter type class ([#259](https://github.com/cucumber/cucumber-expressions/pull/259))
 
 ## [17.0.1] - 2023-11-24
 ### Fixed