Make rc announcement mandatory
Make rc announcement mandatory

Last month, when people upgraded their K8S clusters to use Engine 1.13, networking broke for them
because the default forwarding policy changed to `DROP` to increase the security and prevent some
specific network attacks. After a [long discussion on Twitter](https://twitter.com/jbeda/status/826969113801093121)
we realized that while the 1.13-rc releases had been out for months, they hadn't received as much
testing as we wanted because they hadn't been announced through all available channels.

This is a proposal to alter the release process to make sure that release candidate versions are
announced as widely as possible.

Signed-off-by: Jerome Petazzoni <1c920d0bc8aebaf2a9c7615c16f59bbbb3319256@gmail.com>

bonczj/moby-json-file-logger,johnstep/moby-moby,darrenstahlmsft/docker,gschaetz/moby,nawawi/docker,vdemeester/docker,whuwxl/docker,mixja/docker,konstruktoid/docker-1,shishir-a412ed/docker,johnstep/moby-moby,crosbymichael/docker,rancher/docker,tklauser/docker,Ramzec/docker,kojiromike/docker,srust/docker,laijs/docker,kencochrane/docker,mike1729/docker,cyphar/docker,cpuguy83/docker,pramodhkp/moby,KarthikNayak/docker,jwhonce/docker,sdurrheimer/docker,docker/docker,hqhq/moby,shishir-a412ed/docker,unclejack/docker,fcrisciani/docker,justincormack/docker,rremer/moby,dims/docker,konstruktoid/docker-upstream,pramodhkp/moby,charleszheng44/moby,resin-io/docker,naveed-jamil-tenpearls/moby,sarnautov/moby,ndeloof/docker,dsheets/moby,ibuildthecloud/docker,miminar/docker,gjaskiewicz/moby,justincormack/docker,dsheets/moby,SvenDowideit/docker,pramodhkp/moby,miminar/docker,ColinHebert/docker,konstruktoid/docker-upstream,fcrisciani/docker,shishir-a412ed/docker,bearstech/moby,JMesser81/docker,jlhawn/docker,yosifkit/docker,maxamillion/docker,sarnautov/moby,mahak/docker,Syntaxide/docker,trebonian/docker,ColinHebert/docker,lixiaobing10051267/docker,liaoqingwei/docker,tmp6154/docker,pradipd/moby,duglin/docker,haveatry/docker,jimjag/docker,scotttlin/docker,moby/moby,ndeloof/docker,rhatdan/docker,liaoqingwei/docker,nalind/docker,yongtang/docker,noironetworks/docker,dperny/docker,jimjag/docker,AkihiroSuda/docker,amatsus/docker,danyalKhaliq10p/moby,djs55/docker,thaJeztah/docker,SvenDowideit/docker,tophj-ibm/docker,moby/moby,rremer/moby,lixiaobing1/docker,YuPengZTE/docker,yummypeng/docker,resin-io/docker,tonistiigi/docker,jlhawn/docker,scotttlin/docker,madhanrm/docker,jvanz/docker,mahak/docker,jvanz/docker,x1022as/docker,POLJM242/docker,yasiramin10p/moby,bonczj/moby-json-file-logger,bearstech/moby,x1022as/docker,kencochrane/docker,sterchelen/docker,mike1729/docker,dccurtis/docker,gjaskiewicz/moby,yongtang/docker,nawawi/docker,duglin/docker,prertik/docker,KingEmet/docker,JMesser81/docker,dccurtis/docker,cyphar/docker,tklauser/docker,prertik/docker,x1022as/docker,estesp/docker,darrenstahlmsft/docker,konstruktoid/docker-upstream,darrenstahlmsft/moby,nalind/docker,lixiaobing10051267/docker,moypray/docker,crosbymichael/docker,mahak/docker,raja-sami-10p/moby,gjaskiewicz/moby,jthelin/docker,mikebrow/docker,thaJeztah/docker,rancher/docker,moby/moby,Syntaxide/docker,kojiromike/docker,ndeloof/docker,coreos/docker,Mokolea/docker,mixja/docker,shhsu/docker,dccurtis/docker,haveatry/docker,SvenDowideit/docker,dperny/docker,Syntaxide/docker,lixiaobing10051267/docker,whuwxl/docker,noironetworks/docker,YuPengZTE/docker,allencloud/docker,laijs/moby,duglin/docker,naveed-jamil-tenpearls/moby,pradipd/moby,tophj-ibm/docker,dmcgowan/docker,trebonian/docker,jthelin/docker,gnailuy/docker,tmp6154/docker,konstruktoid/docker-1,danyalKhaliq10p/moby,ibuildthecloud/docker,mikebrow/docker,Ramzec/docker,allencloud/docker,yosifkit/docker,imkin/moby,tianon/docker,Mokolea/docker,laijs/docker,sterchelen/docker,gnailuy/docker,mtesselH/docker,moby/moby,hqhq/moby,rhatdan/docker,tklauser/docker,amatsus/docker,POLJM242/docker,flavio/docker,jimjag/docker,laijs/docker,darrenstahlmsft/moby,gnailuy/docker,allencloud/docker,kojiromike/docker,tmp6154/docker,nawawi/docker,johnstep/moby-moby,shhsu/docker,dmcgowan/docker,gschaetz/moby,Ramzec/docker,rancher/docker,docker/docker,vdemeester/docker,thaJeztah/docker,darrenstahlmsft/docker,paralin/docker,estesp/docker,crosbymichael/docker,KingEmet/docker,docker/docker,imkin/moby,AkihiroSuda/docker,ripcurld0/moby,moul/docker,KingEmet/docker,moypray/docker,bearstech/moby,raja-sami-10p/moby,tonistiigi/docker,ripcurld0/moby,kencochrane/docker,yosifkit/docker,ripcurld0/moby,sdurrheimer/docker,fcrisciani/docker,srust/docker,ibuildthecloud/docker,Mokolea/docker,tonistiigi/docker,AkihiroSuda/docker,ibuildthecloud/docker,jameszhan/docker,justincormack/docker,kolyshkin/moby,jvanz/docker,trebonian/docker,pradipd/moby,shhsu/docker,tophj-ibm/moby,djs55/docker,srust/docker,raja-sami-10p/moby,dims/docker,nawawi/docker,trebonian/docker,miminar/docker,mahak/docker,tophj-ibm/moby,AkihiroSuda/docker,kolyshkin/moby,mike1729/docker,gschaetz/moby,danyalKhaliq10p/moby,moul/docker,coolljt0725/docker,PatrickLang/moby,nalind/docker,madhanrm/docker,noironetworks/docker,charleszheng44/moby,moul/docker,darrenstahlmsft/moby,paralin/docker,cyphar/docker,Ramzec/docker,tophj-ibm/docker,flavio/docker,jameszhan/docker,jwhonce/docker,Mokolea/docker,bonczj/moby-json-file-logger,sterchelen/docker,sdurrheimer/docker,moypray/docker,cpuguy83/docker,nalind/docker,madhanrm/docker,yummypeng/docker,unclejack/docker,jlhawn/docker,gnailuy/docker,thaJeztah/docker,kolyshkin/docker,maxamillion/docker,resin-io/docker,flavio/docker,tophj-ibm/moby,laijs/moby,maxamillion/docker,cpuguy83/docker,whuwxl/docker,konstruktoid/docker-upstream,kolyshkin/moby,paralin/docker,lixiaobing1/docker,tianon/docker,haveatry/docker,charleszheng44/moby,dperny/docker,moul/docker,laijs/moby,mikebrow/docker,mtesselH/docker,hqhq/moby,dmcgowan/docker,bearstech/moby,KarthikNayak/docker,djs55/docker,jameszhan/docker,ColinHebert/docker,mixja/docker,estesp/docker,yasiramin10p/moby,PatrickLang/moby,amatsus/docker,flavio/docker,imkin/moby,dims/docker,prertik/docker,lixiaobing1/docker,vdemeester/docker,KarthikNayak/docker,yongtang/docker,unclejack/docker,dsheets/moby,cpuguy83/docker,naveed-jamil-tenpearls/moby,yummypeng/docker,sarnautov/moby,kolyshkin/docker,JMesser81/docker,mtesselH/docker,konstruktoid/docker-1,rhatdan/docker,coolljt0725/docker,mkumatag/docker,jwhonce/docker,coreos/docker,mkumatag/docker,coolljt0725/docker,coreos/docker,rremer/moby,liaoqingwei/docker,paralin/docker,yasiramin10p/moby,yosifkit/docker,mkumatag/docker,scotttlin/docker,jimjag/docker,PatrickLang/moby,YuPengZTE/docker,ibuildthecloud/docker