Start on 0.18.1.

NEWS

@@ -1,3 +1,5 @@
+0.18.1	UNRELEASED
+
 0.18.0	2017-07-31
 
  BUG FIXES

dulwich/__init__.py

@@ -22,4 +22,4 @@
 
 """Python implementation of the Git file formats and protocols."""
 
-__version__ = (0, 18, 0)
+__version__ = (0, 18, 1)

setup.py

@@ -11,7 +11,7 @@ from distutils.core import Distribution
 import os
 import sys
 
-dulwich_version_string = '0.18.0'
+dulwich_version_string = '0.18.1'
 
 include_dirs = []
 # Windows MSVC support