Support Google Cloud Translate V2 gem

[pnikrat]

Adjust code so that we can support both V1 and V2 gem versions of Google Cloud translate.

Bonus:

• Upgrade Ruby to 2.7.4
• Fix issue Cloud translation removes newline characters #142
• Fix issue Fix tests #98
• Fix issue Rails 6.1 Update #159

[pnikrat]

Failure:
WelcomeTest#test_shoud_properly_save_default_value [/lit/test/integration/lit/welcome_test.rb:109]:
Expected false to be truthy.


Failure:
WelcomeControllerTest#test_should_properly_store_key_with_default_value [/lit/test/functional/welcome_controller_test.rb:36]:
Expected: nil
  Actual: "Default content"

Maciej, I'm having trouble with those two tests. They only fail on Rails 6.1 Appraisal. I know default translation content was fuc*ked up in Rails 6.1 upstream but it was supposed to be fixed by now? I've updated Appraisal to use newest Rails 6.1 patch. Any ideas?

It's working nicely now

[pnikrat]

@mlitwiniuk Added most recent changes