Update rack-oauth2 from 1.2.1 to 1.2.3.
Removes methods deprecated in Rails 5. Working toward #14286 (moved).
Changelog: https://github.com/nov/rack-oauth2/compare/v1.2.1...v1.2.3
Do not update/delete: Banner broadcast message test data
Do not update/delete: Notification broadcast message test data
Removes methods deprecated in Rails 5. Working toward #14286 (moved).
Changelog: https://github.com/nov/rack-oauth2/compare/v1.2.1...v1.2.3