Improve logic for detecting msys2-based Python (works for 3.11 and 3.…

[cr1901]

…12).

The MSYS2 project standardized sysconfig names for 3.12, resulting in errors such as the following after an upgrade:

$ pdm run -v test.py pipx
INFO: Reusing existing script environment: C:/Users/William/AppData/Local/pdm/pdm/venvs/2fa106ce3fc8b29bf047ce91804516ef
Traceback (most recent call last):
  File "C:/msys64/home/William/Projects/python/pdm/src/pdm/models/in_process/env_spec.py", line 25, in <module>
    print(json.dumps(get_current_env_spec(), indent=2))
                     ^^^^^^^^^^^^^^^^^^^^^^
  File "C:/msys64/home/William/Projects/python/pdm/src/pdm/models/in_process/env_spec.py", line 16, in get_current_env_spec
    "platform": str(Platform.current()),
                    ^^^^^^^^^^^^^^^^^^
  File "C:/msys64/home/William/Projects/python/dep-logic/src/dep_logic/tags/platform.py", line 164, in current
    return cls(os_, Arch.parse(architecture))
                    ^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:/msys64/home/William/Projects/python/dep-logic/src/dep_logic/tags/platform.py", line 390, in parse
    return cls(arch)
           ^^^^^^^^^
  File "C:/msys64/mingw64/lib/python3.12/enum.py", line 757, in __call__
    return cls.__new__(cls, value)
           ^^^^^^^^^^^^^^^^^^^^^^^
  File "C:/msys64/mingw64/lib/python3.12/enum.py", line 1171, in __new__
    raise ve_exc
ValueError: 'x86_64_msvcrt_gnu' is not a valid Arch

This PR slightly changes the logic introduced by pdm-project/pdm#3158 for detecting the arch in the MSYS2 case (works for 3.12 and while I don't have 3.11 to test right now, I checked that the mingw_x86_64 string also triggers my updated logic.