Specify Python 3.6 support

Author: hugovk

Diff for: README.md

@@ -19,7 +19,7 @@ If it is not in your `PATH`, you can help GitPython find it by setting
 the `GIT_PYTHON_GIT_EXECUTABLE=<path/to/git>` environment variable.
 
 * Git (1.7.x or newer)
-* Python 2.7 to 3.5, while python 2.6 is supported on a *best-effort basis*.
+* Python 2.7 to 3.6, while python 2.6 is supported on a *best-effort basis*.
 
 The list of dependencies are listed in `./requirements.txt` and `./test-requirements.txt`.
 The installer takes care of installing them for you.
@@ -125,7 +125,7 @@ Please have a look at the [contributions file][contributing].
 
 ### How to verify a release
 
-Please only use releases from `pypi` as you can verify the respective source 
+Please only use releases from `pypi` as you can verify the respective source
 tarballs.
 
 This script shows how to verify the tarball was indeed created by the authors of

Diff for: setup.py

@@ -101,6 +101,7 @@ def _stamp_version(filename):
     package_data={'git.test': ['fixtures/*']},
     package_dir={'git': 'git'},
     license="BSD License",
+    python_requires='>=2.6, !=3.0.*, !=3.1.*, !=3.2.*',
     requires=['gitdb2 (>=2.0.0)'],
     install_requires=install_requires,
     test_requirements=test_requires + install_requires,