Upgrade premailer-rails from 1.9.0 to 1.9.2
Includes compatibility with Rails 5.
Changelog: https://github.com/fphilipe/premailer-rails/blob/master/CHANGELOG.md#v19 2
Working towards #14286 (moved).
cc: @rspeicher
Do not update/delete: Banner broadcast message test data
Do not update/delete: Notification broadcast message test data
Includes compatibility with Rails 5.
Changelog: https://github.com/fphilipe/premailer-rails/blob/master/CHANGELOG.md#v19 2
Working towards #14286 (moved).
cc: @rspeicher