Bug#895834: ITP: python-dataclasses -- Python dataclasses backport from 3.7

[Joel Cross <joel+debbugs@kazbak.co.uk>]

Package: wnpp
Severity: wishlist
Owner: Joel Cross <joel+debbugs@kazbak.co.uk>

* Package name    : python-dataclasses
  Version         : 0.5
  Upstream Author : Eric V. Smith <eric@python.org>
* URL             : https://github.com/ericvsmith/dataclasses
* License         : MIT
  Programming Lang: Python
  Description     : Python dataclasses backport from 3.7

This is a backport of the dataclasses feature that will be made available in
Python 3.7 (see https://www.python.org/dev/peps/pep-0557).
Many libraries are already being built that depend upon this feature - with
this packaged, these libraries will be able to have support in Python 3.6 as
well as the upcoming Python 3.7.