Update Rails (#8141)

* Update Rails

* fix Update Rails

spec/controllers/concerns/signature_verification_spec.rb

@@ -105,7 +105,7 @@ describe ApplicationController, type: :controller do
         end
 
         it 'returns nil when body has been tampered' do
-          request.headers['RAW_POST_DATA'] = 'doo doo doo'
+          post :success, body: 'doo doo doo'
           expect(controller.signed_request_account).to be_nil
         end
       end