trivial: Do not show a warning when building the libfwupdplugin introspection
trivial: Do not show a warning when building the libfwupdplugin introspection

If new enough add Xmlb into the libfwupdplugin GIR includes.

hughsie/fwupd,hughsie/fwupd,fwupd/fwupd,hughsie/fwupd,fwupd/fwupd,fwupd/fwupd,hughsie/fwupd,fwupd/fwupd