- update to 2.6.0:
* Add support for Django up to 1.10.
* Remove support for Django<1.7
* Properly handle `^0.X.Y` in a NPM-compatible way
* According to SemVer 2.0.0, build numbers aren't ordered.
* Remove specs of the ``Spec('<1.1.3+')`` form
* Comparing ``Version('0.1.0')`` to ``Version('0.1.0+bcd')`` has new
rules
* :func:`semantic_version.compare` returns ``NotImplemented`` when its
parameters differ only by build metadata
* ``Spec('<=1.3.0')`` now matches ``Version('1.3.0+abde24fe883')``
* Fix handling of bumping pre-release versions, thanks to @minchinweb.
* Add support for NPM-style ``^1.2.3`` and ``~2.3.4`` specs, thanks to @skwashd
* Fix tests for Django 1.7+, thanks to @mhrivnak.
- convert to singlespec