upgrade version to 0.3.1-c
upgrade version to 0.3.1-c

librelois/duniter-currency-monit,duniter/duniter-currency-monit,duniter/duniter-currency-monit,librelois/duniter-currency-monit,librelois/duniter-special-node-members,duniter/duniter-currency-monit,duniter/duniter-currency-monit