fix(compat): PY3-check must hold even for PY4

Author: ankostis

gitdb/utils/compat.py

@@ -1,7 +1,7 @@
 import sys
 
 
-PY3 = sys.version_info[0] == 3
+PY3 = sys.version_info[0] >= 3
 
 try:
     from itertools import izip