PhotonX [1] filed a deletion request for skypeforlinux-beta-bin [2]:

This time the package can be removed for sure because MS disabled support for version 5.5.x and login fails with a corresponding message.

[1] https://aur.archlinux.org/account/PhotonX/ [2] https://aur.archlinux.org/pkgbase/skypeforlinux-beta-bin/