Added missing version hints

- made shutil.disk_uage only available for Python >= 3.3
diff --git a/docs/conf.py b/docs/conf.py
index be550dc..f40e506 100644
--- a/docs/conf.py
+++ b/docs/conf.py
@@ -63,9 +63,9 @@
 # built documents.
 #
 # The short X.Y version.
-version = '2.9'
+version = '3.0'
 # The full version, including alpha/beta/rc tags.
-release = '2.9'
+release = '3.0'
 
 # The language for content autogenerated by Sphinx. Refer to documentation
 # for a list of supported languages.
@@ -139,7 +139,7 @@
 # The name for this set of Sphinx documents.
 # "<project> v<release> documentation" by default.
 #
-# html_title = 'pyfakefs v2.9'
+# html_title = 'pyfakefs v3.0'
 
 # A shorter title for the navigation bar.  Default is the same as html_title.
 #