fix TypeErrors "object is not subscriptable"

The type hint shoudld be List[] instead of list[] [1] and TypeError:
'ABCMeta' object is not subscriptable (using instead typing.Callable).

[1]: https://mail.python.org/pipermail/python-dev/2017-April/147818.html

dangerzone/container.py

@@ -5,8 +5,7 @@ import platform
 import shutil
 import subprocess
 import tempfile
-from collections.abc import Callable
+from typing import Callable, List, Optional
-from typing import List, Optional
 
 import appdirs