Remove Dockerfile syntax from frozen features
Remove Dockerfile syntax from frozen features

As discussed on the maintainers mailinglist,
and during a maintainers review session;

We've recently made changes to the Dockerfile
syntax (e.g., `HEALTHCHECK`, `SHELL`), so
mentioning the Dockerfile syntax as a frozen
feature is no longer accurate.

Removing it from frozen features does NOT
automatically state an intent to make big
changes to the syntax; making changes
to the syntax are important decisions and
should never be taken lightly.

This change is just to indicate that we
can *accept* changes if they are meaningful,
and we're confident they can be made.

Signed-off-by: Sebastiaan van Stijn <64b2b6d12bfe4baae7dad3d018f8cbf6b0e7a044@gone.nl>

icaoweiwei/docker,stevvooe/docker,cpuguy83/docker,mtanlee/docker,portworx/docker,hqhq/moby,johnstep/moby-moby,dperny/docker,moypray/docker,kolyshkin/moby,yp-engineering/docker,whuwxl/docker,PatrickLang/moby,darrenstahlmsft/moby,KarthikNayak/docker,srust/docker,dccurtis/docker,sarnautov/moby,dgageot/docker,raja-sami-10p/moby,paralin/docker,charleszheng44/moby,jlhawn/docker,liaoqingwei/docker,tmp6154/docker,mstanleyjones/docker,laijs/docker,amatsus/docker,mike1729/docker,cpuguy83/docker,scotttlin/docker,allencloud/docker,dperny/docker,duglin/docker,yasiramin10p/moby,konstruktoid/docker-upstream,gjaskiewicz/moby,alfred-landrum/docker,catinthesky/docker,lixiaobing10051267/docker,naveed-jamil-tenpearls/moby,cloudflare/docker,michael-holzheu/docker,gschaetz/moby,konstruktoid/docker-1,vdemeester/docker,liaoqingwei/docker,nalind/docker,xiaods/docker,tklauser/docker,akira-baruah/docker,sdurrheimer/docker,asbjornenge/docker,q384566678/docker,gnailuy/docker,qudongfang/docker,scotttlin/docker,prertik/docker,laijs/moby,yummypeng/docker,flavio/docker,cpuguy83/docker,ajaymdesai/docker,paralin/docker,jimjag/docker,JMesser81/docker,tagomoris/docker,justincormack/docker,thaJeztah/docker,rancher/docker,amatsus/docker,jimjag/docker,shishir-a412ed/docker,mkumatag/docker,diogomonica/docker,naveed-jamil-tenpearls/moby,resin-io/docker,pramodhkp/moby,charleszheng44/moby,kunalkushwaha/docker,JMesser81/docker,srust/docker,yosifkit/docker,afein/docker,SvenDowideit/docker,xiekeyang/docker,kencochrane/docker,ffoysal/docker,dccurtis/docker,michelvocks/docker,nawawi/docker,moul/docker,maxamillion/docker,trebonian/docker,POLJM242/docker,YuPengZTE/docker,harche/docker,shishir-a412ed/docker,tonistiigi/docker,cpuguy83/docker,ajaymdesai/docker,paralin/docker,djs55/docker,estesp/docker,tophj-ibm/moby,jthelin/docker,coreos/docker,rremer/moby,lixiaobing10051267/docker,KarthikNayak/docker,trebonian/docker,endophage/docker,diogomonica/docker,jimjag/docker,jameszhan/docker,mtrmac/docker,djs55/docker,dgageot/docker,gschaetz/moby,x1022as/docker,scotttlin/docker,lixiaobing10051267/docker,justincormack/docker,unclejack/docker,dgageot/docker,yasiramin10p/moby,ndeloof/docker,erikh/docker,jlhawn/docker,13W/docker,tophj-ibm/moby,docker/docker,kolyshkin/docker,moul/docker,jhorwit2/docker,mikedougherty/docker,yosifkit/docker,KingEmet/docker,trebonian/docker,gjaskiewicz/moby,sarnautov/moby,sdurrheimer/docker,mstanleyjones/docker,shhsu/docker,ColinHebert/docker,KarthikNayak/docker,jvanz/docker,nalind/docker,laijs/moby,moby/moby,dccurtis/docker,danyalKhaliq10p/moby,flavio/docker,darrenstahlmsft/docker,msabansal/docker,dims/docker,tonistiigi/docker,splunk/docker,brahmaroutu/docker,laijs/docker,mtesselH/docker,thaJeztah/docker,moul/docker,Mokolea/docker,mtesselH/docker,erikh/docker,yosifkit/docker,KingEmet/docker,eskaaren/docker,mtrmac/docker,coolljt0725/docker,yummypeng/docker,justincormack/docker,mikebrow/docker,kolyshkin/moby,mahak/docker,ibuildthecloud/docker,tianon/docker,alfred-landrum/docker,lixiaobing1/docker,tophj-ibm/docker,cloudflare/docker,duglin/docker,darrenstahlmsft/moby,ibuildthecloud/docker,mikedougherty/docker,Ramzec/docker,dsheets/moby,gnailuy/docker,coolljt0725/docker,xiekeyang/docker,ripcurld0/moby,q384566678/docker,jhorwit2/docker,Syntaxide/docker,jvanz/docker,qudongfang/docker,miminar/docker,tonistiigi/docker,jwhonce/docker,crosbymichael/docker,ripcurld0/moby,mkumatag/docker,Syntaxide/docker,unclejack/docker,pramodhkp/moby,noironetworks/docker,unclejack/docker,POLJM242/docker,jwhonce/docker,tophj-ibm/docker,diogomonica/docker,tklauser/docker,portworx/docker,harche/docker,nawawi/docker,pradipd/moby,mahak/docker,YuPengZTE/docker,jimjag/docker,tianon/docker,maxamillion/docker,kolyshkin/moby,allencloud/docker,AkihiroSuda/docker,tklauser/docker,dims/docker,mtanlee/docker,imkin/moby,mikedougherty/docker,yp-engineering/docker,ripcurld0/moby,thtanaka/docker,rhatdan/docker,asbjornenge/docker,kojiromike/docker,haveatry/docker,duglin/docker,darrenstahlmsft/moby,bearstech/moby,jameszhan/docker,shishir-a412ed/docker,portworx/docker,nalind/docker,HuKeping/docker,brahmaroutu/docker,endophage/docker,dsheets/moby,mohmost12/docker,mtanlee/docker,mixja/docker,yp-engineering/docker,kojiromike/docker,tagomoris/docker,erikstmartin/docker,darrenstahlmsft/docker,moby/moby,amatsus/docker,kunalkushwaha/docker,HuKeping/docker,tagomoris/docker,bonczj/moby-json-file-logger,vdemeester/docker,madhanrm/docker,mike1729/docker,xiekeyang/docker,kencochrane/docker,mtrmac/docker,charleszheng44/moby,moypray/docker,madhanrm/docker,trebonian/docker,tophj-ibm/moby,ibuildthecloud/docker,allencloud/docker,yongtang/docker,gschaetz/moby,konstruktoid/docker-1,KingEmet/docker,Ramzec/docker,sterchelen/docker,rhatdan/docker,liaoqingwei/docker,coreos/docker,mohmost12/docker,flavio/docker,vdemeester/docker,raja-sami-10p/moby,xiaods/docker,ffoysal/docker,danyalKhaliq10p/moby,sarnautov/moby,miminar/docker,whuwxl/docker,lixiaobing1/docker,yongtang/docker,mikebrow/docker,Ramzec/docker,splunk/docker,ibuildthecloud/docker,gnailuy/docker,sfsmithcha/docker,docker/docker,mtesselH/docker,noironetworks/docker,fcrisciani/docker,sfsmithcha/docker,laijs/docker,moby/moby,dmcgowan/docker,ffoysal/docker,13W/docker,akira-baruah/docker,Ramzec/docker,mike1729/docker,paralin/docker,mikebrow/docker,madhanrm/docker,13W/docker,srust/docker,laijs/moby,konstruktoid/docker-upstream,estesp/docker,kojiromike/docker,msabansal/docker,noironetworks/docker,xiaods/docker,asbjornenge/docker,erikstmartin/docker,rancher/docker,michael-holzheu/docker,rhatdan/docker,rremer/moby,kunalkushwaha/docker,crosbymichael/docker,docker/docker,icaoweiwei/docker,moby/moby,ndeloof/docker,estesp/docker,whuwxl/docker,kencochrane/docker,cyphar/docker,erikstmartin/docker,Syntaxide/docker,eskaaren/docker,mohmost12/docker,nawawi/docker,konstruktoid/docker-upstream,cyphar/docker,prertik/docker,miminar/docker,mkumatag/docker,dmcgowan/docker,mixja/docker,tmp6154/docker,alfred-landrum/docker,brahmaroutu/docker,ColinHebert/docker,yummypeng/docker,ndeloof/docker,JMesser81/docker,nawawi/docker,catinthesky/docker,ibuildthecloud/docker,hqhq/moby,SvenDowideit/docker,jthelin/docker,sfsmithcha/docker,sterchelen/docker,danyalKhaliq10p/moby,prertik/docker,coolljt0725/docker,13W/docker,thtanaka/docker,cyphar/docker,raja-sami-10p/moby,eskaaren/docker,afein/docker,yasiramin10p/moby,resin-io/docker,kolyshkin/docker,tmp6154/docker,bonczj/moby-json-file-logger,dmcgowan/docker,thaJeztah/docker,AkihiroSuda/docker,stevvooe/docker,jvanz/docker,tophj-ibm/docker,shhsu/docker,mahak/docker,crosbymichael/docker,nalind/docker,afein/docker,icaoweiwei/docker,hqhq/moby,ajaymdesai/docker,HuKeping/docker,splunk/docker,Mokolea/docker,sterchelen/docker,qudongfang/docker,gjaskiewicz/moby,erikh/docker,pramodhkp/moby,mixja/docker,yongtang/docker,AkihiroSuda/docker,ColinHebert/docker,djs55/docker,naveed-jamil-tenpearls/moby,dims/docker,flavio/docker,mstanleyjones/docker,cloudflare/docker,rancher/docker,johnstep/moby-moby,thaJeztah/docker,x1022as/docker,13W/docker,pradipd/moby,moypray/docker,resin-io/docker,endophage/docker,bearstech/moby,xuxinkun/docker,maxamillion/docker,fcrisciani/docker,imkin/moby,HideoYamauchi/docker,jameszhan/docker,dsheets/moby,rremer/moby,mahak/docker,fcrisciani/docker,AkihiroSuda/docker,bearstech/moby,konstruktoid/docker-1,jhorwit2/docker,yosifkit/docker,q384566678/docker,darrenstahlmsft/docker,shhsu/docker,jwhonce/docker,HideoYamauchi/docker,YuPengZTE/docker,xuxinkun/docker,michelvocks/docker,imkin/moby,michelvocks/docker,bearstech/moby,dperny/docker,michael-holzheu/docker,moul/docker,msabansal/docker,Mokolea/docker,Mokolea/docker,coreos/docker,xuxinkun/docker,lixiaobing1/docker,HideoYamauchi/docker,bonczj/moby-json-file-logger,harche/docker,stevvooe/docker,pradipd/moby,SvenDowideit/docker,johnstep/moby-moby,konstruktoid/docker-upstream,sdurrheimer/docker,x1022as/docker,thtanaka/docker,jlhawn/docker,haveatry/docker,PatrickLang/moby,haveatry/docker,catinthesky/docker,gnailuy/docker,PatrickLang/moby