Merge pull request #2056 from ThomasWaldmann/remove-dot-github

remove .github from pypi package, fixes #2051

MANIFEST.in

@@ -5,5 +5,6 @@ recursive-exclude docs *.pyc
 recursive-exclude docs *.pyo
 prune docs/_build
 prune .travis
+prune .github
 exclude .coveragerc .gitattributes .gitignore .travis.yml Vagrantfile
 include borg/_version.py