PIP deprecation warning while installing Textual

Under Windows 10,

pip install "textual[dev]"

resulted in

DEPRECATION: mkdocs-exclude is being installed using the legacy 'setup.py install' method, because it does not have a 'pyproject.toml' and the 'wheel' package is not installed. pip 23.1 will enforce this behaviour change. A possible replacement is to enable the '--use-pep517' option. Discussion can be found at https://github.com/pypa/pip/issues/8559

Thought you'd want to know...