test: use built-in collection types for type hints (Python 3.9 / PEP 585)

Since Python 3.9, type hinting has become a little less awkward, as for
collection types one doesn't need to import the corresponding
capitalized types (`Dict`, `List`, `Set`, `Tuple`, ...) anymore, but can
use the built-in types directly. [1] [2]
This commit applies the replacement for all Python scripts (i.e. in the
contrib and test folders) for the basic types:
    - typing.Dict  -> dict
    - typing.List  -> list
    - typing.Set   -> set
    - typing.Tuple -> tuple

[1] https://docs.python.org/3.9/whatsnew/3.9.html#type-hinting-generics-in-standard-collections
[2] https://peps.python.org/pep-0585/#implementation for a list of type

contrib/devtools/utils.py

@@ -8,10 +8,9 @@ Common utility functions
 import shutil
 import sys
 import os
-from typing import List
 
 
-def determine_wellknown_cmd(envvar, progname) -> List[str]:
+def determine_wellknown_cmd(envvar, progname) -> list[str]:
     maybe_env = os.getenv(envvar)
     maybe_which = shutil.which(progname)
     if maybe_env: