Updates in v 2.0.9 break when running on python 3.9

[LawrenceK]

Stack Trace

from pyfcm import FCMNotification

File "/usr/local/lib/python3.9/site-packages/pyfcm/init.py", line 14, in
from .fcm import FCMNotification
File "/usr/local/lib/python3.9/site-packages/pyfcm/fcm.py", line 1, in
from .baseapi import BaseAPI
File "/usr/local/lib/python3.9/site-packages/pyfcm/baseapi.py", line 26, in
class BaseAPI(object):
File "/usr/local/lib/python3.9/site-packages/pyfcm/baseapi.py", line 31, in BaseAPI
service_account_file: str | None = None,
TypeError: unsupported operand type(s) for |: 'type' and 'NoneType'

This is from commit c8a47fc