codegen: Use new builder_postprocess attribute
codegen: Use new builder_postprocess attribute

Signed-off-by: Daniel Silverstone <3cc17a76d780e0cd3d87bad586a1c53967be5625@digital-scurf.org>

EPashkin/gir,GuillaumeGomez/gir,gtk-rs/gir,gtk-rs/gir,gtk-rs/gir,GuillaumeGomez/gir,GuillaumeGomez/gir,EPashkin/gir