Small security update

Technical: Just a small security update this morning to disable TLS 1.0 and 1.1 and set 1.2 as our minimum.

This affects around 0.1% of our traffic so we're not expecting anyone to notice as 1.2 is widely in use now.

Anyone experiencing connection issues as of 09:30 this morning will need to update their software stack to make sure TLS 1.2 is supported.