Fix the retry error class

spec/uploadcare/entity/uploader_spec.rb

@@ -88,7 +88,7 @@ module Entity
             VCR.use_cassette('upload_upload_from_url') do
               url = 'https://placekitten.com/2250/2250'
               error_str = 'Upload is taking longer than expected. Try increasing the max_request_tries config if you know your file uploads will take more time.' # rubocop:disable Layout/LineLength
-              expect { subject.upload(url) }.to raise_error(RequestError, error_str)
+              expect { subject.upload(url) }.to raise_error(RetryError, error_str)
             end
           end
         end