Fix UpgradeOptions.printUpgradesOnly. Fixes #323.
Fix UpgradeOptions.printUpgradesOnly. Fixes #323.

This commit disables fetching upgrade candidates and prints a message for each upgradeable dependency instead.

alexeibs/dub,y12uc231/dub,D-Programming-Language/dub,Abscissa/dub,dreamsxin/dub,schuetzm/dub,gedaiu/dub,grogancolin/dub,jeanbaptistelab/dub,Abscissa/dub-data-mod,rjframe/dub,Geod24/dub,Flamaros/dub,nazriel/dub,xentec/dub,p0nce/dub,jelmansouri/dub