introspection.m4: Update from g-i
introspection.m4: Update from g-i

This fixes substitution with dash.

Unity-Technologies/gtk,Unity-Technologies/gtk,Unity-Technologies/gtk,Distrotech/gtk,johne53/MB3Gtk-2,johne53/MB3Gtk-2,johne53/MB3Gtk-2,Distrotech/gtk,Distrotech/gtk,johne53/MB3Gtk-2,Distrotech/gtk,Unity-Technologies/gtk,johne53/MB3Gtk-2,Distrotech/gtk,Unity-Technologies/gtk