pyproject.toml missing

[leo-schick]

When installing with pip I get the deprecation warning:

DEPRECATION: pytest-dependency 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 pypa/pip#8559

A pyproject.toml file should be added to the project. See also https://snarky.ca/what-the-heck-is-pyproject-toml/ for a sample pyproject.toml file