Namespace deprecation is causing breaking changes

[petewalker]

Describe the bug

Your method of deprecation whilst moving generators out into namespaces is causing breaking changes when using methods like unique

To Reproduce

name = Faker::Dog.unique.name
# NoMethodError:
#       undefined method `unique' for Faker::Dog:Class

Expected behavior

A deprecation notice is raised, no errors:

name = Faker::Dog.unique.name
# NOTE: Faker::Dog.unique.name is deprecated; use Faker::Creature::Dog.unique.name instead. It will be removed on or after 2019-01-01.

Additional context

Because you've moved these classes into modules, you're no longer inheriting from Base.

[vbrazo]

@petewalker we've just released a new version and this issue should disappear. Thanks for reporting this issue!

[vbrazo]

btw Faker::Dog.unique.name is now Faker::Creature::Dog.unique.name