fix: add PreviousGtidsEvent check

Author: heehehe

pymysqlreplication/tests/test_basic.py

@@ -1788,6 +1788,7 @@ def test_get_none_invalid(self):
 
         self.assertIsInstance(self.stream.fetchone(), RotateEvent)
         self.assertIsInstance(self.stream.fetchone(), FormatDescriptionEvent)
+        self.assertIsInstance(self.stream.fetchone(), PreviousGtidsEvent)
         self.assertIsInstance(self.stream.fetchone(), QueryEvent)
         self.assertIsInstance(self.stream.fetchone(), TableMapEvent)