`av==9.1.1` wheels seem to be be not packaged properly for Windows and Python 3.8/9

Created by: pmeier

Overview

av==9.1.1 wheel released a couple of hours ago seems to be not packaged properly for Windows and Python 3.8 and 3.9.

Expected behavior

Import without issues.

Actual behavior

Traceback (most recent call last):
  File "C:\Users\circleci\project\test\datasets_utils.py", line 90, in _import
    module = importlib.import_module(package)
  File "C:\Users\circleci\project\env\lib\importlib\__init__.py", line 127, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "<frozen importlib._bootstrap>", line 1014, in _gcd_import
  File "<frozen importlib._bootstrap>", line 991, in _find_and_load
  File "<frozen importlib._bootstrap>", line 975, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 671, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 843, in exec_module
  File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed
  File "C:\Users\circleci\project\env\lib\site-packages\av\__init__.py", line 44, in <module>
    from av._core import time_base, library_versions
ImportError: DLL load failed while importing _core: The specified module could not be found.

Investigation

CI runs:

Reproduction

import av

Versions

OS: Windows
PyAV runtime: 9.1.1