Update changelog

CHANGELOG.md

@@ -6,6 +6,7 @@ New Feature
 - Adds a new profile class ``PowerProfile`` for raising profiles to a power.
 - Adds an option ``scaled_termination`` (defaults to True) to all of the desc optimizers to measure the norms for ``xtol`` and ``gtol`` in the scaled norm provided by ``x_scale`` (which defaults to using an adaptive scaling based on the Jacobian or Hessian). This should make things more robust when optimizing parameters with widely different magnitudes. The old behavior can be recovered by passing ``options={"scaled_termination": False}``.
 - ``desc.objectives.Omnigenity`` is now vectorized and able to optimize multiple surfaces at the same time. Previously it was required to use a different objective for each surface.
+- Adds a new objective ``desc.objectives.MirrorRatio`` for targeting a particular mirror ratio on each flux surface, for either an ``Equilibrium`` or ``OmnigenousField``.
 
 Bug Fixes