version up : Zope-2.12.20 including security fixes.

http://zope2.zope.org/news/security-vulnerability-announcement-cve-2011-3587

stack/erp5.cfg

@@ -30,7 +30,7 @@ allow-hosts =
 
 extends =
 # Exact version of Zope
-  http://svn.zope.org/repos/main/Zope/tags/2.12.19/versions.cfg
+  http://svn.zope.org/repos/main/Zope/tags/2.12.20/versions.cfg
   ../component/logrotate/buildout.cfg
   ../component/dcron/buildout.cfg
   ../component/file/buildout.cfg