Avoid using deprecated gdk_pixbuf_new_from_inline()
As reported by Simon McVittie firstname.lastname@example.org:
" […] gdk_pixbuf_new_from_inline() is deprecated.
A gdk-pixbuf maintainer recommends using GBytes and new_from_bytes(), which is also what pygobject does in its own overrides
 on gdk-pixbuf!17 (merged) "
This code is based by the one @smcv suggested, edited by myself to support the case when $data is an array ref that contains unpacked bytes, like the previous implementation did.