Cannot use Pathlike objects with from_file

[cjosey]

The supported arguments to from_file and related is str. Passing a pathlib Path results in:

Traceback (most recent call last):
  File "[path]/process.py", line 8, in <module>
    tape = ENDFtk.tree.Tape.from_file(p)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
TypeError: from_file(): incompatible function arguments. The following argument types are supported:
    1. (filename: str) -> ENDFtk.tree.Tape

Invoked with: PosixPath('[filename]')

Converting to str works just fine. I have no idea if it is possible to make this more user-friendly with the PyBind11 stuff.