Mdform

----------------

- Nothing has changed yet.

----------------

- Migrated project structure to use pyproject.toml.
- Migrated typing to PEP585.
- Python 3.8 is no longer supported.

------------------

- Fixed bug in FloatField defining min, max or step.
- Changed FloatField representation to .f[min:max:step]
(notice the trailing f).
- Added DecimalField with representation .[min:max:step:places].
- Added tests for Fields.
- Fixed parsing bug in RadioField / CheckBoxField for labels with
more than 1 letter.

------------------

- Add parse convenience function.
- Improve docs.

----------------

- Migrated fields to use dataclasses
- Added typing information
- Improved testing and coverage

----------------

- Added typing information.
- Reorganize code and base classes.