[PRQ#50868] Deletion Request for ruby2.6

MarsSeed [1] filed a deletion request for ruby2.6 [2]: Unneeded legacy Ruby version; fails to build on current Arch Linux. Safe to delete. Regarding its current consumers: - pygmy-legacy is discontinued since 2019 and should not be used according to upstream (PRQ#50867), - mkxp-git's PKGBUILD was last changed in 2020, and its current upstream needs a different Ruby version. [1] https://aur.archlinux.org/account/MarsSeed/ [2] https://aur.archlinux.org/pkgbase/ruby2.6/