Create cache dir with string

[SKernchen]

At the Moment the HermesContext requires a Path. In the Past we made it optional and converted path or string to Path.
In https://github.com/softwarepub/hermes/blob/feature/153-refactor-datamodel/src/hermes/model/context_manager.py#L48

def __init__(self, project_dir: t.Optional[Path] = None):
        """
        Create a new context for the given project dir.

        :param project_dir: The root directory of the project.
                            If nothing is given, the current working directory is used.
        """

        #: Base dir for the hermes metadata cache (default is `.hermes` in the project root).
        self.hermes_dir = Path(project_dir or '.') / self.hermes_cache_name

[led02]

Actually, I don't like this idea. We are expecting a path here. Using pathlib.Path helps to keep platform independence and avoids mis-use...

[SKernchen]

Ok then I adapted the tests to work with Paths in Pull Request #382

[sdruskat]

I'm assuming that this can now be closed.
@SKernchen, re-open if more work is necessary.