add core-deps/libportal.bst
We can no longer use the version from freedesktop-sdk as it now depends on gtk4.
We need to coordinate the merge within all modules at once: eog!115 (merged) epiphany!1051 (merged) gnome-builder!486 (merged) nautilus!749 (merged)
P.S: this depends on !1417 (merged) being merged first.
Edited by Abderrahim Kitouni