macOs installation fails arm64_sonoma

[Alessio Delmonti]

Describe the bug
Provided instructions to install on macOs do not work correctly with Python 3.8

How to reproduce

1. run brew install pipx
2. run pipx ensurepath will output

Traceback (most recent call last):
  File "/Users/<user>/Library/Python/3.8/bin/pipx", line 6, in <module>
    from pipx.main import cli
ModuleNotFoundError: No module named 'pipx'

Expected behavior
Install pipx correctly

[Jason Lam]

@Alexintosh Could you provide the output of which pipx?