Fix
- correctly generate enum default values (275)
- correctly generate type annotations
fix: do not generate default dataclass docstrings
fix: datetime model generation
the previous implementation did not roundtrip
feat: render docstrings in generated classes
fix: correct union and optional conversion
test: add avsc -> python -> avsc roundtrip test
fix: properly handle aliases in the model generator
tests: add coverage for single-type unions model generation
Co-authored-by: Maximilian Hils <gitmaximilianhils.com>