Update HMP Birmingham yaml file
Update HMP Birmingham yaml file

As of April 2019 HMP Birmingham became a publicly run prison and a
visitor recently pointed out that our site still states that it's a
private prison.  Whilst Birmingham does not use our service to manage
it's bookings it's important that we display the correct/up to date
information to visitors.1

ministryofjustice/prison-visits-2,ministryofjustice/prison-visits-2,ministryofjustice/prison-visits-2,ministryofjustice/prison-visits-2