Update CHANGELOG.md
Update CHANGELOG.md

Add empty lines to cause merge conflicts for PRs not being merged before release of v3.4
bartsch-dev/jabref,Braunch/jabref,motokito/jabref,bartsch-dev/jabref,obraliar/jabref,JabRef/jabref,tobiasdiez/jabref,obraliar/jabref,mredaelli/jabref,obraliar/jabref,zellerdev/jabref,mairdl/jabref,shitikanth/jabref,jhshinn/jabref,motokito/jabref,jhshinn/jabref,Siedlerchr/jabref,grimes2/jabref,zellerdev/jabref,obraliar/jabref,shitikanth/jabref,grimes2/jabref,zellerdev/jabref,motokito/jabref,grimes2/jabref,Siedlerchr/jabref,tobiasdiez/jabref,ayanai1/jabref,shitikanth/jabref,shitikanth/jabref,Braunch/jabref,mairdl/jabref,ayanai1/jabref,ayanai1/jabref,Braunch/jabref,mredaelli/jabref,bartsch-dev/jabref,tschechlovdev/jabref,grimes2/jabref,oscargus/jabref,mredaelli/jabref,bartsch-dev/jabref,oscargus/jabref,Siedlerchr/jabref,tobiasdiez/jabref,oscargus/jabref,tschechlovdev/jabref,JabRef/jabref,Mr-DLib/jabref,sauliusg/jabref,Mr-DLib/jabref,Siedlerchr/jabref,JabRef/jabref,bartsch-dev/jabref,mairdl/jabref,sauliusg/jabref,mairdl/jabref,shitikanth/jabref,sauliusg/jabref,Mr-DLib/jabref,obraliar/jabref,tschechlovdev/jabref,tschechlovdev/jabref,oscargus/jabref,motokito/jabref,jhshinn/jabref,mairdl/jabref,ayanai1/jabref,mredaelli/jabref,jhshinn/jabref,Mr-DLib/jabref,jhshinn/jabref,Braunch/jabref,mredaelli/jabref,grimes2/jabref,Mr-DLib/jabref,motokito/jabref,tobiasdiez/jabref,oscargus/jabref,sauliusg/jabref,ayanai1/jabref,JabRef/jabref,zellerdev/jabref,Braunch/jabref,zellerdev/jabref,tschechlovdev/jabref