Log Message:
py-py: updated to 1.9.0

1.9.0
- Add type annotation stubs for the following modules:

  * ``py.error``
  * ``py.iniconfig``
  * ``py.path`` (not including SVN paths)
  * ``py.io``
  * ``py.xml``

  There are no plans to type other modules at this time.

  The type annotations are provided in external .pyi files, not inline in the
  code, and may therefore contain small errors or omissions. If you use ``py``
  in conjunction with a type checker, and encounter any type errors you believe
  should be accepted, please report it in an issue.

1.8.2
- On Windows, ``py.path.local``s which differ only in case now have the same
  Python hash value. Previously, such paths were considered equal but had
  different hashes, which is not allowed and breaks the assumptions made by
  dicts, sets and other users of hashes.