correct the cookie samesite setting

tes/__init__.py

@@ -13,7 +13,7 @@ app.config['SESSION_REFRESH_EACH_REQUEST'] = True
 app.config['SESSION_COOKIE_NAME'] = 'tessession'
 app.config['SESSION_COOKIE_SECURE'] = True
 app.config['SESSION_COOKIE_HTTPONLY'] = True
-app.config['SESSION_COOKIE_SAMESITE'] = None
+app.config['SESSION_COOKIE_SAMESITE'] = 'None'
 app.config['APPLICATION_ROOT'] = '/'
 if 'FLASK_ENV' in os.environ and os.environ['FLASK_ENV'] == 'development':
     DEV=True