examples/mesos: Change ubuntu VB to be correct version
examples/mesos: Change ubuntu VB to be correct version

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