Add extended registrar's info to "pending_update_request_for_old_registrant" mailer

#180

spec/routing/registrant/domain_update_confirms_routing_spec.rb

@@ -0,0 +1,9 @@
+require 'rails_helper'
+
+RSpec.describe Registrant::DomainUpdateConfirmsController do
+  describe 'routing' do
+    it 'routes to #show' do
+      expect(get: '/registrant/domain_update_confirms/1').to route_to('registrant/domain_update_confirms#show', id: '1')
+    end
+  end
+end