tests/k8s/Vagrantfile: bump K8s VM ram to 3 GB
tests/k8s/Vagrantfile: bump K8s VM ram to 3 GB

There have been Jenkins builds which fail due to thrashing in the K8s build.
The VMs currently only have 1 GB of RAM, which is not enough for running
Kubernetes, etcd, and Cilium as well as application pods.

Signed-off by: Ian Vernon <ian@cilium.io>

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