Update version in cni tutorial
Update version in cni tutorial

Update the cniVersion used in the CNI tutorial so that it works with
containerd 1.2. Containerd 1.2 includes a version of the cri plugin
(release/1.2) that, in turn, includes a version of the
cni library (0.6.0) that only supports up to 0.3.1.
https://github.com/containernetworking/cni/blob/v0.6.0/pkg/version/version.go#L38

PiperOrigin-RevId: 329837188

google/gvisor,google/gvisor,google/gvisor,google/gvisor,google/gvisor,google/gvisor,google/gvisor,google/gvisor