Update CHANGELOG

Author: ManifoldFR

CHANGELOG.md

@@ -14,6 +14,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Changed
 
+- Optimize a bunch of includes
+- core: remove headers `proximal-penalty.hpp`/`proximal-penalty.hxx`
 - Change storage of `CostStack` to `boost::unordered::unordered_map`, pointing to pair of cost function and weight ([#199](https://github.com/Simple-Robotics/aligator/pull/199))
 - Change storage for `ConstraintStack` to using two `std::vector<polymorphic<>>` the struct `StageConstraintTpl` is now merely a convenient API shortcut for the end-user.
 - Remove `StageConstraintTpl::nr()` (in C++ only)