- Fix build without python2

- version update to 6.14.0
6.14.0 (24 Feb 2020)
--------------------
- Add support for non-deterministic logging order when using :meth:`twisted.LogCapture`.
6.13.1 (20 Feb 2020)
--------------------
- Fix for using :func:`compare` to compare two-element :func:`~unittest.mock.call`
objects.
6.13.0 (18 Feb 2020)
--------------------
- Allow any attributes that need to be ignored to be specified directly when calling
:func:`~testfixtures.comparison.compare_object`. This is handy when writing
comparers for :func:`compare`.
6.12.1 (16 Feb 2020)
--------------------
- Fix a bug that occured when using :func:`compare` to compare a string with a
slotted object that had the same :func:`repr` as the string.
6.12.0 (6 Feb 2020)
-------------------
- Add support for ``universal_newlines``, ``text``, ``encoding`` and ``errors`` to
:class:`popen.MockPopen`, but only for Python 3.
6.11.0 (29 Jan 2020)
--------------------
- :class:`decimal.Decimal` now has better representation when :func:`compare` displays a failed
comparison, particularly on Python 2.
- Add support to :func:`compare` for explicitly naming objects to be compared as ``x`` and ``y``.
This allows symmetry with the ``x_label`` and ``y_label`` parameters that are now documented.
- Restore ability for :class:`Comparison` to compare properties and methods, although these uses