Log Message:
math/hs-invariant: Update to 0.6

0.6 [2022.07.03]
* Loosen the Monad constraint in the Invariant(2) instances for Kleisli to
  an Invariant constraint.
* Loosen the Comonad constraint in the Invariant2 instance for Cokleisli to
  an Invariant constraint.
* Add Invariant instances for PastroSum, CopastroSum, Environment,
  FreeMapping, Pastro, and FreeTraversing from the profunctors library.
* Add Invariant(2) instances for Copastro and Coyoneda from the profunctors
  library.

0.5.6 [2022.05.07]
* Add InvariantProfunctor and InvariantArrow newtypes that admit
  implementations of invmap that only require Profunctor or Arrow
  constraints, respectively. Also add top-level invmapProfunctor and
  invmapArrow functions.