prevent public gem pushes by default
prevent public gem pushes by default

fixes #3533
mpapis/bundler,EasonYi/bundler,zhangkuaiji/bundler,bronzdoc/bundler,davydovanton/bundler,tgxworld/bundler,cstrahan/bundler,jingweno/bundler,Elffers/bundler,masarakki/bundler,Teino1978-Corp/Teino1978-Corp-bundler,danimashu/bundler,joshsoftware/bundler,christer155/bundler,steved/bundler,gregkare/bundler,seanlinsley/bundler,ipmobiletech/bundler,anil826/bundler,nju520/bundler,neslom/bundler,RochesterinNYC/bundler,suhastech/bundler,EthanK28/bundler,ximus/bundler,elovelan/bundler,AiyionPrime/bundler,elovelan/bundler,Elffers/bundler,davydovanton/bundler,nju520/bundler,PG-kura/bundler,chulkilee/bundler,h4ck3rm1k3/bundler,patvice/bundler,mdorrance/bundler,simplybusiness/bundler,ngpestelos/bundler,schaary/bundler,Eric-Guo/bundler,ligi/bundler,CorainChicago/bundler,asutoshpalai/bundler,tgxworld/bundler,steved/bundler,frsyuki/bundler,bundler/bundler,simplybusiness/bundler,asymmetric/bundler,asutoshpalai/bundler,masarakki/bundler,patvice/bundler,neslom/bundler,cstrahan/bundler,mattbrictson/bundler-1,schaary/bundler,chef/bundler,seanlinsley/bundler,ximus/bundler,EasonYi/bundler,Eric-Guo/bundler,kohgpat/bundler,lmtim/bundler,pivotal-cf-experimental/bundler,agis-/bundler,AiyionPrime/bundler,agis-/bundler,mvz/bundler,wenderjean/bundler,Wirachmat/bundler,jingweno/bundler,asymmetric/bundler,suhastech/bundler,anil826/bundler,christer155/bundler,Wirachmat/bundler,kohgpat/bundler,mattbrictson/bundler-1,CorainChicago/bundler,philnash/bundler,mpapis/bundler,danimashu/bundler,dilumnavanjana/bundler,zhangkuaiji/bundler,carpodaster/bundler,ngpestelos/bundler,roseweixel/bundler,jasonkarns/bundler,carpodaster/bundler,chef/bundler,cdwort/bundler,cdwort/bundler,philnash/bundler,robinboening/bundler,EthanK28/bundler,bronzdoc/bundler,wenderjean/bundler,ipmobiletech/bundler,roseweixel/bundler,byroot/bundler,h4ck3rm1k3/bundler,robinboening/bundler,RochesterinNYC/bundler,bundler/bundler,joshsoftware/bundler,lmtim/bundler,chulkilee/bundler,jasonkarns/bundler,frsyuki/bundler,mvz/bundler,dilumnavanjana/bundler,mdorrance/bundler,byroot/bundler,gregkare/bundler,ligi/bundler,Teino1978-Corp/Teino1978-Corp-bundler,PG-kura/bundler,pivotal-cf-experimental/bundler