fix homebrew pip upgrade python

[todd-dsm]

Research this error message from Ansible install in tools/install-prep.sh

Update pip...
Requirement already satisfied: pip in /Library/Developer/CommandLineTools/Library/Frameworks/Python3.framework/Versions/3.9/lib/python3.9/site-packages (21.2.4)
Collecting pip
  Downloading pip-25.3-py3-none-any.whl (1.8 MB)
Installing collected packages: pip
  WARNING: The scripts pip, pip3 and pip3.9 are installed in '/Users/thomas/Library/Python/3.9/bin' which is not on PATH.
  Consider adding this directory to PATH or, if you prefer to suppress this warning, use --no-warn-script-location.
Successfully installed pip-25.3
WARNING: You are using pip version 21.2.4; however, version 25.3 is available.
You should consider upgrading via the '/Library/Developer/CommandLineTools/usr/bin/python3 -m pip install --upgrade pip' command.

helper stuff

# find site-packages
% python3 -m site
sys.path = [
    '/Users/thomas/code/smpl/aws/eks-cluster',
    '/opt/homebrew/Cellar/python@3.14/3.14.3_1/Frameworks/Python.framework/Versions/3.14/lib/python314.zip',
    '/opt/homebrew/Cellar/python@3.14/3.14.3_1/Frameworks/Python.framework/Versions/3.14/lib/python3.14',
    '/opt/homebrew/Cellar/python@3.14/3.14.3_1/Frameworks/Python.framework/Versions/3.14/lib/python3.14/lib-dynload',
    '/opt/homebrew/lib/python3.14/site-packages',
    '/opt/homebrew/opt/python@3.14/Frameworks/Python.framework/Versions/3.14/lib/python3.14/site-packages',
]
USER_BASE: '/Users/thomas/Library/Python/3.14' (doesn't exist)
USER_SITE: '/Users/thomas/Library/Python/3.14/lib/python/site-packages' (doesn't exist)
ENABLE_USER_SITE: True