docs: add authors to client architecture doc
docs: add authors to client architecture doc

Signed-off-by: Gyuho Lee <0fbd30d364d71722b926950b451cecd97b54fc29@amazon.com>

ajityagaty/etcd,etcd-io/etcd,gyuho/etcd,mkumatag/etcd,li-ang/etcd,mkumatag/etcd,mqliang/etcd,ajityagaty/etcd,coreos/etcd,etcd-io/etcd,xiang90/etcd,joshix/etcd,rnaveiras/etcd,coreos/etcd,rnaveiras/etcd,li-ang/etcd,xiang90/etcd,dannysauer/etcd,joshix/etcd,ajityagaty/etcd,gyuho/etcd,cockroachdb/etcd,mkumatag/etcd,rnaveiras/etcd,mqliang/etcd,etcd-io/etcd,dannysauer/etcd,cockroachdb/etcd,mqliang/etcd