Add support for the builtin generic types

[poncovka]

From https://docs.python.org/3.9/whatsnew/3.9.html#pep-585-builtin-generic-types:

In type annotations you can now use built-in collection types such as list and dict as generic types instead of importing the corresponding capitalized types (e.g. List or Dict) from typing.

These type hints should be supported by dasbus since Python 3.9.