Fix test_docs

It's not portable to test for a secific author name

Author: Byron

git/test/test_docs.py

@@ -289,9 +289,9 @@ def test_references_and_objects(self, rw_dir):
         assert len(headcommit.hexsha) == 40
         assert len(headcommit.parents) > 0
         assert headcommit.tree.type == 'tree'
-        assert headcommit.author.name == 'Sebastian Thiel'
+        assert len(headcommit.author.name) != 0
         assert isinstance(headcommit.authored_date, int)
-        assert headcommit.committer.name == 'Sebastian Thiel'
+        assert len(headcommit.committer.name) != 0
         assert isinstance(headcommit.committed_date, int)
         assert headcommit.message != ''
         # ![14-test_references_and_objects]