fix: name 'Optional' is not defined

import Optional from typing

Author: wolfram77

pdfly/extract_annotated_pages.py

@@ -5,6 +5,7 @@
 A: https://github.com/py-pdf/pdfly/issues/97
 """
 
+from typing import Optional
 from pathlib import Path
 from pypdf import PdfReader, PdfWriter