Create CONTRIBUTING.md
Create CONTRIBUTING.md

fwupd/fwupd,superm1/fwupd,superm1/fwupd,fwupd/fwupd,fwupd/fwupd,hughsie/fwupd,vathpela/fwupd,hughsie/fwupd,fwupd/fwupd,vathpela/fwupd,hughsie/fwupd,vathpela/fwupd,vathpela/fwupd,superm1/fwupd,hughsie/fwupd