Use au address with matching state, suburb and postcode

ie. if something validates against real addresses and you need the `state`, `suburb` and `postcode` to all be matching
eg. `VIC, Melbourne, 3000`

eg. use in factory:
```ruby
factory :company do
  state_code { Faker::AddressAU.state_abbr }
  post_code  { Faker::AddressAU.postcode(state) }
  suburb     { Faker::AddressAU.suburb(state, post_code) }
end
```