parsl CI builds with deprecated pip feature

[benclifford]

Describe the bug
CI build reports this:

DEPRECATION: Building 'parsl' using the legacy setup.py bdist_wheel mechanism, which will be removed in a future version. pip 25.3 will enforce this behaviour change. A possible replacement is to use the standardized build interface by setting the `--use-pep517` option, (possibly combined with `--no-build-isolation`), or adding a `pyproject.toml` file to the source tree of 'parsl'. Discussion can be found at https://github.com/pypa/pip/issues/6334