add uswitch to users.md
add uswitch to users.md

Signed-off-by: Joseph Irving <ff06a70567aff2468f5b64e59714852fadc34232@uswitch.com>

michi-covalent/cilium,michi-covalent/cilium,michi-covalent/cilium,tgraf/cilium,tgraf/cilium,michi-covalent/cilium,tklauser/cilium,tgraf/cilium,cilium/cilium,tklauser/cilium,cilium/cilium,tklauser/cilium,tklauser/cilium,tgraf/cilium,cilium/cilium,michi-covalent/cilium,cilium/cilium,tgraf/cilium,tklauser/cilium,tgraf/cilium,cilium/cilium,cilium-team/cilium,cilium-team/cilium