Error when using black 21.8b0 black binary on linux

[jalaziz]

Describe the bug

When running the latest black binary on linux, the following error is thrown:

Traceback (most recent call last):
  File "black/__main__.py", line 1, in <module>
  File "PyInstaller/loader/pyimod03_importers.py", line 546, in exec_module
  File "black/__init__.py", line 38, in <module>
  File "PyInstaller/loader/pyimod03_importers.py", line 546, in exec_module
  File "black/nodes.py", line 28, in <module>
  File "PyInstaller/loader/pyimod03_importers.py", line 546, in exec_module
  File "black/cache.py", line 9, in <module>
  File "PyInstaller/loader/pyimod03_importers.py", line 546, in exec_module
  File "platformdirs/__init__.py", line 31, in <module>
  File "platformdirs/__init__.py", line 27, in _set_platform_dir_class
  File "importlib/__init__.py", line 127, in import_module
ModuleNotFoundError: No module named 'platformdirs.unix'
[2725] Failed to execute script '__main__' due to unhandled exception!

This seems to an issue with PyInstaller missing a module during packaging.

To Reproduce

1. Run a linux container: docker run --rm -it debian:stable-slim bash
2. Download the black binary: wget --tries=5 -q -O /usr/local/bin/black https://github.com/psf/black/releases/download/21.8b0/black_linux && chmod +x /usr/local/bin/black
3. Run black: black -v

Expected behavior

The version of black should be printed.

Environment (please complete the following information):

• Version: 21.8b0
• OS and Python version: Linux

Does this bug also happen on main?

N/A?

Additional context

This is likely due to #2375.

This error doesn't occur when using the 21.7b0 binaries. platformdirs.unix may need to be added explicitly using PyInstaller's hidden imports functionality.