docs: update CHANGELOG.md file

CHANGELOG.md

@@ -6,6 +6,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+## [0.9.0] - 2024-03-26
+### Added
+- PNSSet class for parsing and writing `pnsSet.xml` files
+
 ## [0.8.0] - 2022-10-18
 ### Added
 - coordinates and sensor layout XML files for the Geodesic Head Web
@@ -90,7 +94,8 @@ In `Reader.get_physical_samples_from_epoch()`:
 - Parse key elements in categories.xml files with `mffpy.xml_files.Categories` class.
 - Incorporate `cached_property` dependency into `mffpy` library.
 
-[Unreleased]: https://github.com/bel-public/mffpy/compare/v0.8.0...HEAD
+[Unreleased]: https://github.com/bel-public/mffpy/compare/v0.9.0...HEAD
+[0.9.0]: https://github.com/bel-public/mffpy/compare/v0.8.0...v0.9.0
 [0.8.0]: https://github.com/bel-public/mffpy/compare/v0.7.4...v0.8.0
 [0.7.4]: https://github.com/bel-public/mffpy/compare/v0.7.3...v0.7.4
 [0.7.3]: https://github.com/bel-public/mffpy/compare/v0.7.2...v0.7.3