docs/ipsec: use ds/cilium as a target to kubectl exec into
docs/ipsec: use ds/cilium as a target to kubectl exec into

This is also mirror the Wireguard documentation.

Signed-off-by: Alexandre Perrin <60c6d277a8bd81de7fdde19201bf9c58a3df08f4@kaworu.ch>

cilium/cilium,tklauser/cilium,tklauser/cilium,cilium/cilium,michi-covalent/cilium,cilium/cilium,michi-covalent/cilium,tklauser/cilium,michi-covalent/cilium,michi-covalent/cilium,cilium/cilium,tklauser/cilium,michi-covalent/cilium,tklauser/cilium,cilium/cilium