Upgrade Devise from 4.1.1 to 4.2.0.
This fixes an issue with Rails 5 and brings us up-to-date with the latest Devise release. It also deprecates Devise::TestHelpers
in favor of Devise::Test::ControllerHelpers
.
Changelog: https://github.com/plataformatec/devise/blob/v4.2.0/CHANGELOG.md#420---2016-07-01
Working toward #14286 (moved), as always.
cc: @rspeicher