PyGObject 3.9.3 Fixes Numerous Annoying Bugs

PyGObject 3.9.3 adds support for properties of type GInterface, re-implements support for passing GValue’s by reference, adds marshaling of GI_TYPE_TAG_VOID held in a GValue to int, adds GIL safety to pyobject_copy for copying boxed PyObjects, and adds deprecation warning for marshaling arbitrary objects as pointers. This development release of PyGObject also adds callable and descriptor protocols to PyGICallableInfo, cleans up invoke arguments and kwargs combiner code, and ensures exceptions set in closure out argument marshaling are printed.