Request #31711 has been rejected by dbermond [1]: When an upstream software is "rapidly changing" (to quote you), it does not necessarily means that the package needs maintainer action/update. Since the date you provided (april/2021), the package was building and working fine. Only recently at the very last few days, the need of a maintenance action was needed, when the vmaf requirement raised to >= 2.0 (and the package is now updated for this). There is no need to regularly update a VCS package if it does not need maintainer action. Please don't send orphan requests in this situation.
[1] https://aur.archlinux.org/account/dbermond/
