Add changelog

Author: albertomercurio

CHANGELOG.md

@@ -13,6 +13,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Fix `smesolve` for specifying initial state as density matrix. ([#395])
 - Add more generic solver for `steadystate_floquet` to allow more linear solvers. ([#396])
 - Fix time evolution output when using `saveat` keyword argument. ([#398])
+- Improve ensemble generation of `ssesolve` and change parameters handling on stochastic processes. ([#403])
 
 ## [v0.26.0]
 Release date: 2025-02-09
@@ -128,3 +129,4 @@ Release date: 2024-11-13
 [#395]: https://github.com/qutip/QuantumToolbox.jl/issues/395
 [#396]: https://github.com/qutip/QuantumToolbox.jl/issues/396
 [#398]: https://github.com/qutip/QuantumToolbox.jl/issues/398
+[#403]: https://github.com/qutip/QuantumToolbox.jl/issues/403