Update gitpython to 3.0.0

[pyup-bot]

This PR updates gitpython from 2.1.8 to 3.0.0.

Changelog

2.1.12

==============================

* Multi-value support and interface improvements for Git configuration. Thanks to A. Jesse Jiryu Davis.

or run have a look at the difference between tags v2.1.11 and v2.1.12:
https://github.com/gitpython-developers/GitPython/compare/2.1.11...2.1.12

2.1.11

=================

see the following for (most) details:
https://github.com/gitpython-developers/gitpython/milestone/26?closed=1

or run have a look at the difference between tags v2.1.10 and v2.1.11:
https://github.com/gitpython-developers/GitPython/compare/2.1.10...2.1.11

2.1.10

=================

see the following for (most) details:
https://github.com/gitpython-developers/gitpython/milestone/25?closed=1

or run have a look at the difference between tags v2.1.9 and v2.1.10:
https://github.com/gitpython-developers/GitPython/compare/2.1.9...2.1.10

2.1.9 - Dropping support for Python 2.6
=======================================

see the following for (most) details:
https://github.com/gitpython-developers/gitpython/milestone/24?closed=1

or run have a look at the difference between tags v2.1.8 and v2.1.9:
https://github.com/gitpython-developers/GitPython/compare/2.1.8...2.1.9

Links

• PyPI: https://pypi.org/project/gitpython
• Changelog: https://pyup.io/changelogs/gitpython/
• Repo: https://github.com/gitpython-developers/GitPython
• Docs: https://pythonhosted.org/GitPython/

[pyup-bot]

Closing this in favor of #77