Update CONTRIBUTING.md
Update CONTRIBUTING.md

minor edit
andrewsomething/pkgcloud,Phanatic/pkgcloud,dionjwa/pkgcloud,pkgcloud/pkgcloud,mcanthony/pkgcloud,Hopebaytech/pkgcloud,apla/pkgcloud,DonSchenck/pkgcloud,bunglestink/pkgcloud,hacor/pkgcloud,songanbui/pkgcloud,temka1234/pkgcloud,Phanatic/pkgcloud,mdsummers/pkgcloud