Bump version number

configure.ac

@@ -18,7 +18,7 @@ dnl You should have received a copy of the GNU General Public License
 dnl along with Dynare.  If not, see <https://www.gnu.org/licenses/>.
 
 AC_PREREQ([2.62])
-AC_INIT([dynare-preprocessor], [4.8-unstable])
+AC_INIT([dynare-preprocessor], [6-unstable])
 AC_CONFIG_AUX_DIR([build-aux])
 AC_CONFIG_SRCDIR([src/DynareMain.cc])
 AM_INIT_AUTOMAKE([1.11 -Wall -Wno-portability foreign no-dist-gzip dist-xz tar-pax])