Proposal: Add the `update` operation

[utam0k]

How about adding the update operation, which is used in the real world, if you don't mind me asking?¹²
https://github.com/opencontainers/runtime-spec/blob/main/runtime.md#operations

Also, we already have checkBeforeUpdate for the update operation.
https://github.com/opencontainers/runtime-spec/blob/main/config-linux.md#memory

Footnotes

1. https://github.com/kubernetes/enhancements/tree/master/keps/sig-node/1287-in-place-update-pod-resources#cri-changes ↩

2. https://github.com/containerd/containerd/blob/a5a4c9ce04d11f4437263b14a2b7b3b8a21e8a0c/pkg/process/init.go#L466 ↩

[utam0k]

I can make the draft PR if needed.