Update dependencies for Ruby (2017-12-03) (#5878)

* Update active_model_serializers to version 0.10.7

* Update capistrano-rails to version 1.3.1

* Update capistrano-rbenv to version 2.1.3

* Update capybara to version 2.16.1

* Update devise-two-factor to version 3.0.2

* Update i18n-tasks to version 0.8.19

* Update ox to version 2.8.2

* Update parallel_tests to version 2.19.0

* Update puma to version 3.11.0

* Update redis-namespace to version 1.6.0

* Update rspec-rails to version 3.7.2

* Update scss_lint to version 0.56.0

* Update webmock to version 3.1.1

* Update webpush to version 0.3.3

* bundle update