dav1d and aom SONAME bump


Next week I will update dav1d to version 0.4.0 which includes a SONAME bump,
and will do a GIT snapshot of aom, whose library is unstable.

I will push these updates both on F31 and F30, so consumers of these libraries
(ffmpeg, xine-lib, vlc) will need to rebuild their packages on both release.

Best regards,