Update gradle from 4.2.1 to 4.3
Update gradle from 4.2.1 to 4.3

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