Rules

- Dropped support for Python 2
- Dropped support for Django versions before 2.2

- Added support for Django v3.0

- Added ability to automatically check for permissions in Drango Rest Framework
viewsets.
- Added ability to automatically check for permissions in Drango class-based
views.
- Added ability to automatically register permissions for models.
- Added shim for "six" in anticipation for Django 3.0 dropping support for
Python 2 and removing "six" from its codebase.

- Fixed issue with using ``rules`` in ``CreateView`` CBV

- Dropped support for Python 2.6 and 3.3
- Dropped support for Django versions before 1.11
- Removed ``SkipPredicate`` exception and ``skip`` method of ``Predicate``
- Removed ``replace_rule`` and related APIs
- Added ``set_rule`` and related APIs to safely replace a rule without having
to ensure one already exists
- Added compatibility with Django v2.1
- Re-introduced support for PyPy and PyPy 3
- Changed Python and Django supported versions policy to exclude end-of-life
versions. Support for EOL'd versions will be dropped in minor version
updates of ``rules`` from now on.

- Fixed masking AttributeErrors raised from CBV get_object
- Fixed compatibility with `inspect` in newer Python 3 versions
- Added ability to replace rules and permissions