upgrade to Zope 4.0b8 (#559)

versions.cfg

@@ -2,7 +2,7 @@
 # This file is part of buildout.coredev repository: https://github.com/plone/buildout.coredev
 # The plone release team is responsible for it,
 # if you have suggestions, please open an issue at: https://github.com/plone/buildout.coredev/issues
-extends = http://dist.plone.org/versions/zope-4-0-b7-versions.cfg
+extends = https://raw.githubusercontent.com/zopefoundation/Zope/4.0b8/versions.cfg
 
 [versions]
 ##############################################################################
@@ -71,15 +71,15 @@ Products.PythonScripts = 4.2
 Products.StandardCacheManagers = 4.0.1
 tempstorage = 4.0.1
 zc.relation = 1.1.post2
-zc.sourcefactory = 1.0.0
+zc.sourcefactory = 1.1
 ZODB3 = 3.11.0
 zope.app.intid = 3.7.1
 zope.app.locales = 4.0.1
-zope.copy = 4.2.0
+zope.copy = 4.2
 zope.copypastemove = 4.1.0
 zope.dublincore = 4.2.0
 zope.intid = 4.3.0
-zope.keyreference = 4.1.0
+zope.keyreference = 4.2.0
 zope.mkzeoinstance = 4.1
 zope.password = 4.3.1
 
@@ -292,9 +292,6 @@ plone.jsonserializer                  = 0.9.6
 Chameleon = 3.4
 chameleon = 3.4
 
-# Versions that depend on Zope 4.0b6
-Products.PythonScripts = 4.2
-
 [versions:python27]
 towncrier = 18.5.0
 trollius = 2.2