Log Message:
py-gobject: updated to 2.28.7

2.28.7:
- Move property and signal creation into _class_init()
- gio-types.defs: change some enums to flags
- Fix set_qdata warning on accessing NULL gobject property
- Disable introspection support by default
- Don't install codegen for Python 3
- Ship tests/te_ST@nouppera in release tarballs for tests to succeed
- [gi] Port test_properties from static gio to GI Gio
- [python3] fix build. PYcairo_IMPORT doesn't exists anymore
- [python3] Fix maketrans import
- [gi-overrides] fix MessageBox so it correctly handles the type constructor param
- gdbus tests: Fix hang if test case fails
- Fix crash in Gtk.TextIter overrides
- correctly initialize the _gi_cairo_functions array to be zero filled
- [gtk-override] print warning if user imports Gtk 2.0
- Add support for enums in gobject.property