Similar to https://github.com/thoughtbot/administrate/pull/1960, this deprecation was introduced in Rails 6.1. For example:
DEPRECATION WARNING: action_view.raise_on_missing_translations is
deprecated and will be removed in Rails 6.2. Set i18n.raise_on_missing_translations
instead. Note that this new setting also affects how missing translations
are handled in controllers. (called from load at ./bin/rspec:7)