Bump pkutils -- python 3.13/14 support

Installing on python 3.14:

```
             register_finder(pkgutil.ImpImporter, find_on_path)
                                ^^^^^^^^^^^^^^^^^^^
            AttributeError: module 'pkgutil' has no attribute 'ImpImporter'. Did you mean: 'zipimporter'?
            [end of output]
      
```
The  `ImpImporter` class was removed in Python 3.12