Updated changelog for next version

CHANGELOG.md

@@ -2,8 +2,18 @@
 
 All notable changes to this project will be documented in this file.
 
+
 ## Unreleased
 
+### Added
+### Changed
+### Deprecated
+### Removed
+### Fixed
+
+
+## [0.5.1] - 2025-09-26
+
 ### Added
 - [#1527](https://github.com/pints-team/pints/pull/1527) Added a `ComposedBoundaries` class that lets you compose multiple `Boundaries` classes into a higher dimensional one.
 - [#1500](https://github.com/pints-team/pints/pull/1500) Added a `CensoredGaussianLogLikelihood` class that calculates the censored Gaussian log-likelihood.
@@ -13,8 +23,6 @@ All notable changes to this project will be documented in this file.
 - [#1698](https://github.com/pints-team/pints/pull/1698) CMA-ES now raises a more informative exception when an unsupported 1-d optimisation is attempted.
 - [#1503](https://github.com/pints-team/pints/pull/1503) Stopped showing time units in controller logs, because the units change depending on the output type (see #1467).
 - [#1699](https://github.com/pints-team/pints/pull/1699) PINTS is no longer tested on Python 3.7. Testing for Python 3.12 and 3.13 has been added.
-### Deprecated
-### Removed
 ### Fixed
 - [#1517](https://github.com/pints-team/pints/pull/1517) Fixed a major bug in the covariance matrix update for xNES.
 - [#1505](https://github.com/pints-team/pints/pull/1505) Fixed issues with toy problems that accept invalid inputs.