Fix: Use array_key_exists() instead of isset()
Fix: Use array_key_exists() instead of isset()

staabm/composer,fabpot/composer,SpacePossum/composer,gencer/composer,andrerom/composer,composer/composer,alcohol/composer,floverdevel/composer,stefangr/composer,stof/composer,nicolas-grekas/composer,erasys/composer,vdm-io/composer,dzuelke/composer,pierredup/composer,slbmeh/composer,milleruk/composer,johnstevenson/composer,naderman/composer,localheinz/composer