archivers/py-zipstream-ng: Update to 1.6.0

ChangeLog:
https://github.com/pR0Ps/zipstream-ng/blob/master/CHANGELOG.md#v160

* Add the ability to provide a custom "walk" function to
  ZipStream.add_path for more control over how directories are walked.
* Change the exception raised when trying to add a file that doesn't exist
  from a ValueError to a more appropriate FileNotFoundError.
* Optimize the number of os.stat calls required to add a file.
* Fix issue where adding data with an arcname that contained a null byte
  would lead to an incorrect size being calculated.
* When ZipStream.add is provided a size alongside an iterable, the size
  will now be used to determine if Zip64 extensions are needed.

PR:		271746