delete CONTRIBUTING.md in all repos
delete CONTRIBUTING.md in all repos

Some repos still have this file in their document root. We provide one
into .github/CONTRIBUTING.md, so we need to delete the duplicate one.

voxpupuli/modulesync_config,puppet-community/modulesync_config,dhoppe/modulesync_config,voxpupuli/modulesync_config,dhoppe/modulesync_config,voxpupuli/modulesync_config,voxpupuli/modulesync_config,dhoppe/modulesync_config,dhoppe/modulesync_config