fix type hint compatibility with Python < 3.11

extract_otp_secret_keys.py

@@ -41,6 +41,7 @@
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
+from __future__ import annotations  # for compatibility with Python < 3.11
 import argparse
 import base64
 import csv

setup.py

@@ -1,3 +1,4 @@
+from __future__ import annotations  # for compatibility with Python < 3.11
 import pathlib
 from setuptools import setup  # type: ignore
 

test_extract_otp_secret_keys_pytest.py

@@ -18,6 +18,7 @@
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
+from __future__ import annotations  # for compatibility with Python < 3.11
 import io
 import os
 import pathlib

test_extract_otp_secret_keys_unittest.py

@@ -18,6 +18,7 @@
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
+from __future__ import annotations  # for compatibility with Python < 3.11
 import io
 import os
 import sys

test_extract_qrcode_unittest.py

@@ -18,6 +18,7 @@
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
+from __future__ import annotations  # for compatibility with Python < 3.11
 import unittest
 
 import extract_otp_secret_keys