Increase version number

--HG--
branch : 7.0

tryton/tryton/__init__.py

@@ -1,6 +1,6 @@
 # This file is part of Tryton.  The COPYRIGHT file at the top level of
 # this repository contains the full copyright notices and license terms.
-__version__ = "7.0.27"
+__version__ = "7.0.28"
 import locale
 
 import gi