Log Message:
py-rope: updated to 0.18.0

Release 0.18.0:
- Fix `Worder.get_primary_at` for names that start like
  keywords.
- Add guess_def_lineno() to get actual function/class
  definition line number
- Fix SimilarFinder/_ASTMatcher to consider 1/0 and True/False
  to be unequal
- Compatibility with Python 3.8
- Add pytest.ini to collect all tests