ukify: Add more mypy options

This achieves parity with the mypy config used in mkosi.

The import of builtins is needed because otherwise type is attempted to be
resolved to the variable in the scope.

src/ukify/mypy.ini

@@ -1,8 +1,9 @@
 [mypy]
 python_version = 3.9
-allow_redefinition = True
 # belonging to --strict
 warn_unused_configs = true
+disallow_any_generics = true
+disallow_subclassing_any = true
 disallow_untyped_calls = true
 disallow_untyped_defs = true
 disallow_untyped_decorators = true

src/ukify/ukify.py

@@ -20,6 +20,7 @@
 # pylint: disable=unnecessary-lambda-assignment
 
 import argparse
+import builtins
 import collections
 import configparser
 import contextlib
@@ -1386,9 +1387,9 @@ class ConfigItem:
     name: Union[str, tuple[str, str]]
     dest: Optional[str] = None
     metavar: Optional[str] = None
-    type: Optional[Callable] = None
+    type: Optional[Callable[[str], Any]] = None
     nargs: Optional[str] = None
-    action: Optional[Union[str, Callable]] = None
+    action: Optional[Union[str, Callable[[str], Any], builtins.type[argparse.Action]]] = None
     default: Any = None
     version: Optional[str] = None
     choices: Optional[tuple[str, ...]] = None