Fixed date issue if timezone is UT and a 2 digit year

[ferrisbuellers]

Had an error on a production system where an email date header was set to: Wed, 26 Jul 23 17:21:17 UT

I've updated the regex so it matches as the email has a 2-digit year and the regex was only matching 4-digit years.

Tested on production and this update fixes the issue. Hopefully, all is fine with this change.

Can see the regex change here: https://regex101.com/r/EIQBIj/1