[PRQ#42470] Deletion Request for mingw-w64-gst-libav-git

MarsSeed [1] filed a deletion request for mingw-w64-gst-libav-git [2]: Abandoned VCS package from 2019. Does not build latest gst-libav anymore, after gstreamer repo restructuring. [1] https://aur.archlinux.org/account/MarsSeed/ [2] https://aur.archlinux.org/pkgbase/mingw-w64-gst-libav-git/