Bump to 1.8.1 to republish the wheel with correct version

ChangeLog

@@ -4,6 +4,13 @@ Pylint's ChangeLog
 What's New in Pylint 1.8?
 =========================
+Release date: 2017-12-15
+
+    * Wrong version number in __pkginfo__.
+
+What's New in Pylint 1.8?
+=========================
+
 Release date: 2017-12-15
     * Respect disable=... in config file when running with --py3k.

pylint/__pkginfo__.py

@@ -27,7 +27,7 @@ from setuptools import __version__ as setuptools_version
 modname = distname = 'pylint'
-numversion = (1, 8, 0)
+numversion = (1, 8, 1)
 version = '.'.join([str(num) for num in numversion])
 install_requires = [