Switch the fco_digital host to not start with `www`
Switch the fco_digital host to not start with `www`

- The alias can start with `www` instead.
- I hypothesise that this is why Fastly is showing `Fastly error:
  unknown domain` when accessing www.digital.fco.gov.uk despite it
  correctly pointing at us via CNAME.

alphagov/transition-config,alphagov/transition-config