update xmlunit from 2.3.0 -> 2.4.0
update xmlunit from 2.3.0 -> 2.4.0

oscargus/jabref,JabRef/jabref,Siedlerchr/jabref,tobiasdiez/jabref,sauliusg/jabref,sauliusg/jabref,Siedlerchr/jabref,Siedlerchr/jabref,Siedlerchr/jabref,shitikanth/jabref,JabRef/jabref,zellerdev/jabref,zellerdev/jabref,oscargus/jabref,zellerdev/jabref,zellerdev/jabref,shitikanth/jabref,zellerdev/jabref,JabRef/jabref,oscargus/jabref,sauliusg/jabref,oscargus/jabref,sauliusg/jabref,shitikanth/jabref,tobiasdiez/jabref,oscargus/jabref,shitikanth/jabref,tobiasdiez/jabref,shitikanth/jabref,tobiasdiez/jabref,JabRef/jabref