Update checkstyle from 8.7 -> 8.8
Update checkstyle from 8.7 -> 8.8

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