Update obs-beta from 28.0.0-rc2 to 28.1.0-rc1 (#14970)
Update obs-beta from 28.0.0-rc2 to 28.1.0-rc1 (#14970)

* Update obs-beta from 28.0.0-rc2 to 28.1.0-rc1

* obs-beta: update livecheck

Co-authored-by: Sam Ford <0ca8a4bfe5c5e61f6c29b211ba5263c8e9cfe2e1@users.noreply.github.com>
mahori/homebrew-cask-versions