Bump to maven-findbugs 2.4.0.
Bump to maven-findbugs 2.4.0.

wfxiang08/metrics,kevintvh/metrics,mveitas/metrics,thelastpickle/metrics,Banno/metrics,infusionsoft/yammer-metrics,valery1707/dropwizard-metrics,mveitas/metrics,dropwizard/metrics,gorzell/metrics,gburton1/metrics,AltitudeDigital/metrics,gorzell/metrics,scullxbones/metrics-scala,tempredirect/metrics,maciej/metrics-scala,bentatham/metrics,mtakaki/metrics,jasw/metrics,mt0803/metrics,ChetnaChaudhari/metrics,cirrus-dev/metrics,jplock/metrics,dropwizard/metrics,fcrepo4-archive/metrics,randomstatistic/metrics,egymgmbh/metrics,dropwizard/metrics,slovdahl/metrics,wickedshimmy/metrics-scala,ind9/metrics,mattnelson/metrics,ohr/metrics,gorzell/metrics,erikvanoosten/metrics-scala,slachiewicz/metrics,infusionsoft/yammer-metrics,timezra/metrics,mnuessler/metrics,mspiegel/metrics,signalfx/metrics,gburton1/metrics,unitsofmeasurement/metrics,chenxianghua2014/metrics,fcrepo4-archive/metrics,rexren/metrics