Trigger event in validate command
Trigger event in validate command

This allows plugins to run additional validations.

MoT3rror/composer,johnstevenson/composer,alcohol/composer,fabiang/composer,jreinke/composer,gencer/composer,yaman-jain/composer,curry684/composer,hirak/composer,naderman/composer,SpacePossum/composer,stefangr/composer,phansys/composer,till/composer,erasys/composer,milleruk/composer,pierredup/composer,localheinz/composer,andrerom/composer,vdm-io/composer,fabpot/composer,JBleijenberg/composer,dzuelke/composer,balbuf/composer,floverdevel/composer,slbmeh/composer,Soullivaneuh/composer,composer/composer,stof/composer,nicolas-grekas/composer,remicollet/composer,davidolrik/composer,staabm/composer