add changelog entry

Author: nim65s

CHANGELOG.md

@@ -12,6 +12,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 
 ### Added
 * Stub files for Python bindings, using [nanobind's native support](https://nanobind.readthedocs.io/en/latest/typing.html#stub-generation) ([#340](https://github.com/Simple-Robotics/proxsuite/pull/340))
+* Python 3.13 support on PyPI ([#361](https://github.com/Simple-Robotics/proxsuite/pull/361))
 
 ### Changed
 * Change Python bindings to use nanobind instead of pybind11 ([#340](https://github.com/Simple-Robotics/proxsuite/pull/340))