v1.2

• Minor changes (see #36):
  • Change default ToSchema instance for unit data types (i.e. types with one nullable constructor like data Unit = Unit):
    now these types are treated like sum types with only one alternative;
  • Add generic ToParamSchema instance for unit data types;
  • Add items: [] to schema for () (making it a valid schema).
• Fixes:
  • Do not omit items: [] from Schema JSON;
  • Do not generate unused definitions for nested newtypes (see #38).