Integration generator deprecation

[klyonrad]

Closes #2374

With these changes executing rails generate rspec:integration produces the following message

DEPRECATION: 
  The integration generator is deprecated and will be deleted in RSpec-Rails 5. Please use the request generator instead.
 Called from ...../rspec-rails/lib/generators/rspec/integration/integration_generator.rb:18:in `generate_request_spec'

Test Plan

rake generate:app
cd tmp/example_app/
rails generate rspec:integration Bottles
# DEPRECATION: 
#  IntegrationGenerator is deprecated and will be deleted in RSpec 5. Please use `rspec:generator` instead. It should behave in the same way.
# Called from .../rspec-rails/lib/generators/rspec/integration/integration_generator.rb:18:in `generate_request_spec'.
#      create  spec/requests/bottles_spec.rb
rails generate rspec:request Bottles
#    identical  spec/requests/bottles_spec.rb

[klyonrad]

TODO: test out the scaffolds generation

[klyonrad]

I checked the scaffold integration: Fine ✔️

I tried the test suite out what happens lib/generators/rspec/integration/integration_generator.rb is deleted. This helped to catch the now unnecessary require 'generators/rspec/integration/integration_generator' statement 😁

Notes addressed

[pirj]

Thank you!
My apologies that it took us longer to process this. So long that I had to change "will be deleted in RSpec-Rails 5" to "RSpec-Rails 7" 😄

[klyonrad]

@pirj No Problemo. I don't even remember doing this 😂