Fix rubocop issues

app/controllers/spree/credit_cards_controller.rb

@@ -30,7 +30,7 @@ module Spree
         flash[:error] = I18n.t(:card_could_not_be_removed)
       end
       redirect_to account_path(anchor: 'cards')
-    rescue Stripe::CardError => e
+    rescue Stripe::CardError
       flash[:error] = I18n.t(:card_could_not_be_removed)
       redirect_to account_path(anchor: 'cards')
     end

app/models/spree/gateway/stripe_connect.rb

@@ -35,7 +35,7 @@ module Spree
         provider.purchase(*options_for_purchase_or_auth(money, creditcard, gateway_options))
       end
 
-      def void(response_code, creditcard, gateway_options)
+      def void(response_code, _creditcard, gateway_options)
         gateway_options[:stripe_account] = stripe_account_id
         provider.void(response_code, gateway_options)
       end

app/serializers/api/admin/payment_method_serializer.rb

@@ -1,11 +1,15 @@
-class Api::Admin::PaymentMethodSerializer < ActiveModel::Serializer
-  delegate :serializable_hash, to: :method_serializer
+module Api
+  module Admin
+    class PaymentMethodSerializer < ActiveModel::Serializer
+      delegate :serializable_hash, to: :method_serializer
 
-  def method_serializer
-    if object.type == 'Spree::Gateway::StripeConnect'
-      Api::Admin::PaymentMethod::StripeSerializer.new(object)
-    else
-      Api::Admin::PaymentMethod::BaseSerializer.new(object)
+      def method_serializer
+        if object.type == 'Spree::Gateway::StripeConnect'
+          Api::Admin::PaymentMethod::StripeSerializer.new(object)
+        else
+          Api::Admin::PaymentMethod::BaseSerializer.new(object)
+        end
+      end
     end
   end
 end