chore: don't depend on pip

packages shouldn't usually depend on pip unless they actually need it (import from it etc). currently - when installing ta-lib in an uv venv (which usually doensn't come with pip) - pip is installed as dependency of ta-lib. to reproduce: ``` uv venv . .venv/bin/activate uv pip install ta-lib uv pip show pip ``` which outputs: ``` Name: pip Version: 25.2 Location: /home/xmatt/devel/.venv/lib/python3.13/site-packages Requires: Required-by: ta-lib <-- pip is only installed due to ta-lib ``` if dependencies of pip were required (there ain't any) - then these should be listed instead.