be more explicit about required version changes

doc/maintenance.rst

@@ -25,8 +25,8 @@ Steps for creating a new Zope release
 
 - update version information:
 
-  - setup.py
-  - versions.cfg
+  - setup.py (remove dev postfix)
+  - versions.cfg (pin Zope2)
 
 - update docs/CHANGES.rst
 
@@ -40,6 +40,11 @@ Steps for creating a new Zope release
 
     python2.7 setup.py egg_info -RDb '' sdist --formats=zip register upload
 
+- update version information:
+
+  - setup.py (bump version number, add dev postfix)
+  - versions.cfg (remove Zope2 pin)
+
 - check the visible releases on readthedocs.org at (should default to
   showing the active branches)::