Cannot auto-upgrade on windows

[Herringway]

The backup process tries to make a copy of the database with a timestamp in it, which unfortunately has a colon in the filename - a forbidden path character on windows systems. This results in an error like Could not load server: Failed to open datastore: open ircd.db.v22.2024-03-28-23:09:52.253Z.bak: The filename, directory name, or volume label syntax is incorrect.