Update netifaces to 0.11.0

[pyup-bot]

This PR updates netifaces from 0.10.9 to 0.11.0.

Changelog

0.11.0

* Added notice about needing a new maintainer.
 * Fixed link to Travis CI.
 * Added test.py to the source distribution.
 * Fixed netmask calculation for IPv6.
 * Fixes to gateway detection in some edge cases.
 * Build CPython 2.7 wheels for 64-bit Windows (yes, you should be
   using Python 3 now, but still).

 Thank-you to Thomas Sibley, Rajendra Dendukuri, Harshal Patel,
 Jeff Gordon, Sajith Sasidharan and Yuri Sevatz for contributing
 to this release.

Links

• PyPI: https://pypi.org/project/netifaces
• Changelog: https://pyup.io/changelogs/netifaces/
• Repo: https://github.com/al45tair/netifaces