Bump Vala and GObject Introspection requirements.
Bump Vala and GObject Introspection requirements.

This bumps them to their first release in their current stable release
series.

This shrinks the gap between builders' build environments and what our
developers build and test with.

GNOME/folks,GNOME/folks,renatofilho/folks,renatofilho/folks2,renatofilho/folks2,pwithnall/folks,renatofilho/folks,renatofilho/folks2,renatofilho/folks,GNOME/folks,renatofilho/folks,renatofilho/folks2,pwithnall/folks,pwithnall/folks