fix lint that is now better enforced

test/http_date_test.dart

diff --git a/test/http_date_test.dart b/test/http_date_test.dart
index dfcdb4f..d117663 100644
--- a/test/http_date_test.dart
+++ b/test/http_date_test.dart
@@ -28,7 +28,7 @@
     });
 
     test('start of year', () {
-      final date = DateTime.utc(2000, 1, 1, 0, 0, 0);
+      final date = DateTime.utc(2000);
       final formatted = formatHttpDate(date);
 
       expect(formatted, 'Sat, 01 Jan 2000 00:00:00 GMT');