Build warning relating to `setup.py` file

[thunderbiscuit]

When building the library, we now get the following warning:

./bdk-ffi/bdk-python/.localenvironment/lib/python3.11/site-packages/setuptools/_distutils/cmd.py:90: SetuptoolsDeprecationWarning: setup.py install is deprecated.
!!

        ********************************************************************************
        Please avoid running ``setup.py`` directly.
        Instead, use pypa/build, pypa/installer or other
        standards-based tools.

        By 2025-Oct-31, you need to update your project and remove deprecated calls
        or your builds will no longer be supported.

        See https://blog.ganssle.io/articles/2021/10/setup-py-deprecated.html for details.
        ********************************************************************************

!!

[mg-twentyone]

I have created a PR to address this issue. See #13