package/gdk-pixbuf: bump to version 2.42.2

- Switch to meson-package
- Drop GDK_PIXBUF_DISABLE_TESTS as it is not needed anymore (meson
  doesn't build tests when cross-commpiling)

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>