Proposal: SIG label introduction for kubeedge community

[fujitatomoya]

Overview

Currently community repository does not have SIG dedicated labels such as https://github.com/kubeedge/kubeedge/labels/sig%2Fdevice-iot. This proposal to introduce the SIG specific labels to tag on the issue and incoming PRs so that each SIG can focus on their activity related to.

I was not sure if this has been already discussed before, but trying to bring this up for community operation.

Best, Tomoya