arch_boxes_sync: Fix old releases cleanup not working due to NUL character
--output-delimiter="" apparently means use the NUL character[1].
[1] https://git.savannah.gnu.org/cgit/coreutils.git/commit/?id=0e46753d7c9519d7378cd3a4e0951a36ac32ffe7
Due to an influx of spam, we have had to temporarily disable account registrations. Please write an email to accountsupport@archlinux.org, with your desired username, if you want to get access. Sorry for the inconvenience.
--output-delimiter="" apparently means use the NUL character[1].
[1] https://git.savannah.gnu.org/cgit/coreutils.git/commit/?id=0e46753d7c9519d7378cd3a4e0951a36ac32ffe7