Clarify "ownership" of the wg #34
Description
Discussion on SIG Network slack (https://kubernetes.slack.com/archives/C09QYUH5W/p1762983785464329) pointed out that the README here doesn't make it clear who "owns" the plumbing wg. In particular, the fact that it has "k8s" in its name suggests it's part of the Kubernetes project, but in fact it never formally has been. My understanding is that it's a subproject of CNI, but either way, that should be clarified.