bump product version to 5.2.8.0.0+

Change-Id: Ic981e67e4ba8ad1f3f9344c91d6a8338ceb68e3e
diff --git a/configure.ac b/configure.ac
index 2f68ebe..9bc526c 100644
--- a/configure.ac
+++ b/configure.ac
@@ -9,7 +9,7 @@ dnl in order to create a configure script.
# several non-alphanumeric characters, those are split off and used only for the
# ABOUTBOXPRODUCTVERSIONSUFFIX in openoffice.lst. Why that is necessary, no idea.

AC_INIT([LibreOffice],[5.2.7.0.0+],[],[],[http://documentfoundation.org/])
AC_INIT([LibreOffice],[5.2.8.0.0+],[],[],[http://documentfoundation.org/])

AC_PREREQ([2.59])