Update FFmpeg build to use libvpx 1.15.1 and libxml2 2.14.3#1896

jlaine merged 1 commit intoPyAV-Org:mainPyAV-Org/PyAV:mainfrom

jlaine:ffmpeg-7.1.1-3jlaine/PyAV:ffmpeg-7.1.1-3Copy head branch name to clipboard