2.0.0a3

• Added first-class async/await stubbing support: async callables now preserve
  awaitable behavior for thenReturn, thenRaise, and thenAnswer (including
  sync and async answer callables), with parity across when, when2,
  patch, and expect.
  Note that async introspection metadata (e.g. inspect.iscoroutinefunction)
  for stub wrappers is currently implemented only on Python 3.12+.

• Added first-class property/descriptor stubbing support, including class-level property
  stubbing via when(F).p.thenReturn(...) and thenCallOriginalImplementation() support for
  property stubs (including chained answers like
  thenReturn(...).thenCallOriginalImplementation()). Stubbing instance properties now fails
  fast with clear guidance to use class-level stubbing (when(F).p...).