Update public_suffix_list.dat to include mil.uk / mod.uk

[mrtin42]

Added mod.uk and mil.uk second level domains in use by the Ministry of Defense

https://www.nominet.uk/uk-domains/additional-domains/

[dnsguru]

Thank you for taking the time to raise this PR. It is an outstanding example of why this project is reviewed by humans.

As mentioned in issue #1439, where third parties signal changes to entries, especially those delegated TLDs direct from IANA / ICANN namespace, and even more particularly gov/mil, there is validation required.

We would certainly want to see DNS proof to ensure the additions are intentional and deliberate and would involve the appropriate administrative parties, and/or proof of nexus with the affected namespace.

These two submitted are not new namespace. Also, because they have existed for a long period of time, it may be that these are deliberately and intentionally absent in the PSL.

Due to the manner in which presense or absence in the PSL might affect behaviours or how a namespace might be treated by apps or systems that might voluntarily opt to do so, things like the PR are important to confirm are intentional, known changes.

I will be face to face with Nominet Technical staff in two weeks and will review this with them.

[dnsguru]

Nominet was spoken to and they pointed to the whois/rdap records for each of these namespaces as indicating that these are each a public suffix, but did not get confirmation that the cookie affectation or other results of PSL listing were desired by the respective namespace operators.

[dnsguru]

https://www.nominet.uk/lookup/ ->

looking up mod.uk or mil.uk

if you scroll to 'Remarks' section, it states that each is a Public Suffix, and there is an RDAP server listed for them.