nbmake causes pytest deprecation warnings

[lbianchi-lbl]

..\nbmake\pytest_plugin.py:48: 34 warnings
  C:\Miniconda\envs\idaes-pse-dev\lib\site-packages\nbmake\pytest_plugin.py:48: PytestRemovedIn8Warning: The (fspath: py.path.local) argument to NotebookFile is deprecated. Please use the (path: pathlib.Path) argument instead.
  See https://docs.pytest.org/en/latest/deprecations.html#fspath-argument-for-node-constructors-replaced-with-pathlib-path
    return NotebookFile.from_parent(parent, fspath=path)

• Can probably only be addressed upstream (e.g. by an update in nbmake)
• Impact should be limited for the moment (potentially until pytest 8 is released without said nbmake update)