Change CONTRIBUTING.md to use absolute paths
Change CONTRIBUTING.md to use absolute paths

[skip ci]

vadzim/babel,jridgewell/babel,PolymerLabs/babel,hzoo/babel,samwgoldman/babel,guybedford/babel,existentialism/babel,kellyselden/babel,samwgoldman/babel,Skillupco/babel,maurobringolf/babel,chicoxyzzy/babel,kaicataldo/babel,hulkish/babel,jridgewell/babel,maurobringolf/babel,hzoo/babel,PolymerLabs/babel,shuhei/babel,chicoxyzzy/babel,kellyselden/babel,kaicataldo/babel,samwgoldman/babel,jridgewell/babel,jridgewell/babel,hulkish/babel,shuhei/babel,Skillupco/babel,existentialism/babel,chicoxyzzy/babel,claudiopro/babel,Skillupco/babel,kaicataldo/babel,hzoo/babel,Skillupco/babel,babel/babel,shuhei/babel,hulkish/babel,babel/babel,hulkish/babel,kellyselden/babel,claudiopro/babel,claudiopro/babel,existentialism/babel,maurobringolf/babel,babel/babel,vadzim/babel,PolymerLabs/babel,kellyselden/babel,guybedford/babel,chicoxyzzy/babel,babel/babel,hzoo/babel,guybedford/babel,kaicataldo/babel