Changelog for syb-0.7.2.1

2021-01-18 Sergey Vinokurov <serg.foo@gmail.com> * 0.7.2: Add compatibility with GHC 9, switch to tasty for tests, fix tests on GHCJS 2019-06-15 Sergey Vinokurov <serg.foo@gmail.com> * 0.7.1: Define recursive traversals in two parts, non-recursive wrapper and recursive local helper to facilitate inlining and avoid passing the same argument to all recursive calls