Support org scoped projects

[negz]

I don't speak TypeScript very well, but if I follow correctly this Action currently supports only repository scoped projects. It would be ideal if it supported organization scoped project as well.

[negz]

I looked into this today, and it seems like it's unlikely to work well. I think we should be able to optionally iterate over and update a user or an org's projects when we're triggered. The problem is that we'd never get any events when things happened to user or org scoped projects; only issues. So for example dragging a card from one column to another in an org scoped project would not cause the estimates to be updated.