scripts: use latest protodoc to skip grpc-gateway
scripts: use latest protodoc to skip grpc-gateway

protodoc now skips grpc-gateway options

ktateish/etcd,cockroachdb/etcd,rnaveiras/etcd,fanminshi/etcd,StorReduce/etcd,StorReduce/etcd,vimalk78/etcd,YuleiXiao/etcd,tguangch/etcd,handsomesun/etcd,hongchaodeng/etcd,lorneli/etcd,ravigadde/etcd,plasticbox/etcd,ajityagaty/etcd,glycerine/etcd,akauppi/etcd,wantonsolutions/dinv-etcd,jonboulle/etcd,nekto0n/etcd,glevand/coreos--etcd,nekto0n/etcd,bdarnell/etcd,qqsun8819/etcd,OyTao/etcd_learning,mqliang/etcd,westhood/etcd,ajityagaty/etcd,gyuho/etcd,glycerine/etcd,jlamillan/etcd,CrazyJvm/etcd,etcd-io/etcd,swingbach/etcd,yudai/etcd,luxas/etcd,a-robinson/etcd,coreos/etcd,YuleiXiao/etcd,li-ang/etcd,vimalk78/etcd,mkumatag/etcd,heyitsanthony/etcd,purpleidea/etcd,li-ang/etcd,swingbach/etcd,lumjjb/etcd,lorneli/etcd,dannysauer/etcd,coreos/etcd,glevand/coreos--etcd,insequent/etcd,joshix/etcd,endocode/etcd,wantonsolutions/dinv-etcd,purpleidea/etcd,tguangch/etcd,westhood/etcd,xiang90/etcd,rnaveiras/etcd,zaphod-concur/etcd,yudai/etcd,linuxcer/etcd,hongchaodeng/etcd,whuwxl/etcd,visheshnp/etcd,chipironcin/etcd,insequent/etcd,mkumatag/etcd,rchicoli/etcd,bluebreezecf/etcd,jonboulle/etcd,mkumatag/etcd,gyuho/etcd,rnaveiras/etcd,a-robinson/etcd,ajityagaty/etcd,lumjjb/etcd,armstrongli/etcd,cockroachdb/etcd,jlamillan/etcd,bluebreezecf/etcd,xiang90/etcd,sebrandon1/etcd,sebrandon1/etcd,plasticbox/etcd,chipironcin/etcd,heyitsanthony/etcd,armstrongli/etcd,dannysauer/etcd,linuxcer/etcd,akauppi/etcd,ktateish/etcd,luxas/etcd,CrazyJvm/etcd,sofuture/etcd,etcd-io/etcd,etcd-io/etcd,handsomesun/etcd,zaphod-concur/etcd,sinsharat/etcd,mickep76/etcd,qqsun8819/etcd,joshix/etcd,mqliang/etcd,whuwxl/etcd,ravigadde/etcd,OyTao/etcd_learning,rchicoli/etcd,wantonsolutions/dinv-etcd,bdarnell/etcd,visheshnp/etcd,sofuture/etcd,mickep76/etcd,mqliang/etcd,sinsharat/etcd,endocode/etcd,fanminshi/etcd