release: Update CHANGELOG.md for 0.6.4

Author: jcarpent

CHANGELOG.md

@@ -6,6 +6,8 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 
 ## [Unreleased]
 
+## [0.6.4] - 2024-03-01
+
 ### What's Changed
 * Changed `primal_infeasibility_solving` to `False` for feasible QPs ([#302](https://github.com/Simple-Robotics/proxsuite/pull/302))
 
@@ -393,7 +395,8 @@ More to come ([#](a forthcoming release.))
 The first release of ProxSuite.
 
 
-[Unreleased]: https://github.com/Simple-Robotics/proxsuite/compare/v0.6.3...HEAD
+[Unreleased]: https://github.com/Simple-Robotics/proxsuite/compare/v0.6.4...HEAD
+[0.6.4]: https://github.com/Simple-Robotics/proxsuite/compare/v0.6.3...v0.6.4
 [0.6.3]: https://github.com/Simple-Robotics/proxsuite/compare/v0.6.2...v0.6.3
 [0.6.2]: https://github.com/Simple-Robotics/proxsuite/compare/v0.6.1...v0.6.2
 [0.6.1]: https://github.com/Simple-Robotics/proxsuite/compare/v0.6.0...v0.6.1