- update to 2.4.2:
* deepfreeze doesn't change anymore the original object,
- update to 2.4.1:
* In deepfreeze, prefer registered conversions
* Some little fixing to typing
* Documentation typo

- update to 2.3.9:
* Various improvements to type hints
* Fix union of frozendict for python implementation
* Avoid storing empty singleton on class itself in python
implementation
* Now pure py implementation can be built also passing the
`FROZENDICT_PURE_PY` env var with value `1`
* Added type annotations to pyi interface file.
* Numerous improvements to `frozendict` type hints.
* Fixed a regression in sdist packages that made them not
working in the previous release
* Added monkeypatches to `json` and `orjson`, so you can
serialize `frozendict` directly
* Added muslinux builds