Dawiq

What's Changed
* refact: make DataclassDelegate more extensible by JSS95 in https://github.com/JSS95/dawiq/pull/47


**Full Changelog**: https://github.com/JSS95/dawiq/compare/v0.2.0...v0.2.1

What's Changed

* Dataclass type selection is supported.
* ``Optional`` is allowed for more types.
* Property to highlight required field is introduced.
* ``MISSING`` is removed. Data for empty widget is now ``None``.

**Full Changelog**: https://github.com/JSS95/dawiq/compare/v0.1.0...v0.2.0