Version 2.7.1

• Support version 3.13.0 of the GOV.UK Design System #298:
  • Add a #govuk_check_box_divider helper that works in exactly the same way as the radio button divider. It can be used to add a separator, "or" by default, to a list of checkboxes within a #govuk_check_boxes_fieldset. Like the radio variant, the default text can be overridden via a config flag
  • Add a exclusive keyword argument to #govuk_check_box. Exclusive checkboxes will automatically uncheck their siblings when checked, and automatically become unchecked when any of their siblings become checked
  • Add a new section to the guide covering the above features
• Make input element #builder_method private, it doesn't need to be exposed. This was applied to all Element::Input classes #297