uuid database field field not populating for new serial numbers.

[gmn42]

This may be low priority because it doesn't seem to be used for anything (yet), but I have noticed that the new uuid database field is not assigned a uuid for new serial numbers, although the update_156() routine took care to assign them for existing entries.

I was able to address it on the database side with:
ALTER TABLE {$prefix}serial_numbers CHANGE uuid uuid DEFAULT (UUID());
UPDATE {$prefix}serial_numbers SET uuid = UUID() WHERE uuid IS NULL;

Note that default value function seems to require mysql >= 8.0.13 (2018), so I don't know if you want this dependency. See https://stackoverflow.com/questions/46134550/mysql-set-default-id-uuid for alternatives.