ChangeLog: add entry for release serie 1.4

ChangeLog

@@ -15,6 +15,10 @@
 #
 # See the GNU Lesser General Public License in COPYING.LGPL for more details.
 #
+
+StarPU 1.4.0 (svn revision xxxx)
+==============================================
+
 StarPU 1.3.0 (svn revision xxxx)
 ==============================================