op-guide: update performance.md
op-guide: update performance.md

It's been a year, time to refresh with 3.2.0 data.

ajityagaty/etcd,cockroachdb/etcd,visheshnp/etcd,bdarnell/etcd,akauppi/etcd,visheshnp/etcd,lorneli/etcd,armstrongli/etcd,vimalk78/etcd,etcd-io/etcd,gyuho/etcd,bdarnell/etcd,joshix/etcd,YuleiXiao/etcd,sebrandon1/etcd,mickep76/etcd,mqliang/etcd,fanminshi/etcd,glevand/coreos--etcd,mickep76/etcd,mkumatag/etcd,a-robinson/etcd,whuwxl/etcd,etcd-io/etcd,xiang90/etcd,rnaveiras/etcd,gyuho/etcd,fanminshi/etcd,dannysauer/etcd,xiang90/etcd,rnaveiras/etcd,cockroachdb/etcd,armstrongli/etcd,vimalk78/etcd,bluebreezecf/etcd,joshix/etcd,sinsharat/etcd,ajityagaty/etcd,bluebreezecf/etcd,ajityagaty/etcd,sebrandon1/etcd,coreos/etcd,etcd-io/etcd,akauppi/etcd,li-ang/etcd,dannysauer/etcd,mqliang/etcd,li-ang/etcd,YuleiXiao/etcd,heyitsanthony/etcd,a-robinson/etcd,mkumatag/etcd,sinsharat/etcd,mqliang/etcd,glevand/coreos--etcd,mkumatag/etcd,rnaveiras/etcd,lorneli/etcd,heyitsanthony/etcd,whuwxl/etcd,coreos/etcd