Suggestion: Remove all labels

[sburkett]

Somewhat self-explanatory. We have a ton of labels, and when we add new ones, we often have to go back through our actions and fixup all sorts of stuff, remembering to add new labels, use new label names if they get changed, etc. But it would super handy to be able to do something like this:

        uses: andymckay/[email protected]
        with:
          remove-all-labels: true
          add-labels: 'XYZ'