[Python][Packaging] Unexpected directory in wheels

[pitrou]

Describe the bug, including details regarding any error messages, version, and platform.

I noticed our binary wheels have an unexpected directory under the top-level. See below (the pyarrow./ member):

$ wget https://files.pythonhosted.org/packages/
[...]
$ unzip -l pyarrow-15.0.2-cp312-cp312-manylinux_2_28_x86_64.whl 
Archive:  pyarrow-15.0.2-cp312-cp312-manylinux_2_28_x86_64.whl
  Length      Date    Time    Name
---------  ---------- -----   ----
        0  2024-03-13 14:44   pyarrow-15.0.2.dist-info/
        0  2024-03-13 14:44   pyarrow./
        0  2024-03-13 14:44   pyarrow/
[...]

Component(s)

Packaging, Python

[pitrou]

cc @raulcd @jorisvandenbossche

[jorisvandenbossche]

It seems this started with the 6.0.0 release

[pitrou]

Superseded by #43299