bump product version to 7.6.3.1.0+

Change-Id: I920b03d7a7548d1e232055eb0ddb4346336e1a9e
diff --git a/configure.ac b/configure.ac
index 5942829..6d59be2 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],[7.6.3.0.0+],[],[],[http://documentfoundation.org/])
AC_INIT([LibreOffice],[7.6.3.1.0+],[],[],[http://documentfoundation.org/])

dnl libnumbertext needs autoconf 2.68, but that can pick up autoconf268 just fine if it is installed
dnl whereas aclocal (as run by autogen.sh) insists on using autoconf and fails hard