Add tax_category_id to shipping method permitted params

app/controllers/spree/admin/shipping_methods_controller.rb

@@ -86,7 +86,7 @@ module Spree
       def permitted_resource_params
         params.require(:shipping_method).permit(
           :name, :description, :display_on, :require_ship_address, :tag_list, :calculator_type,
-          distributor_ids: [],
+          :tax_category_id, distributor_ids: [],
           calculator_attributes: PermittedAttributes::Calculator.attributes
         )
       end