[PRQ#48319] Deletion Request for mono5

MarsSeed [1] filed a deletion request for mono5 [2]: No package requires this legacy Mono version, which is EOL since 2019. The build is broken as per reported multiple times since 2020-09. Also, this conflicts with extra repo's newer mono. As such, it violates the AUR submission guidelines (AUR packages should not create different or same version builds of repo packages. Non-conflicting builds are okay if there is a need for a different version of the package.) It's safe to delete this superfluous package. [1] https://aur.archlinux.org/account/MarsSeed/ [2] https://aur.archlinux.org/pkgbase/mono5/