py-jedi: updated to 0.18.0

0.18.0
- Dropped Python 2 and Python 3.5
- Using ``pathlib.Path()`` as an output instead of ``str`` in most places:
  - ``Project.path``
  - ``Script.path``
  - ``Definition.module_path``
  - ``Refactoring.get_renames``
  - ``Refactoring.get_changed_files``
- Functions with ``@property`` now return ``property`` instead of ``function``
  in ``Name().type``
- Started using annotations
- Better support for the walrus operator
- Project attributes are now read accessible
- Removed all deprecations

(adam)