One of the core developer's chores is determining if a PR needs to be backported, and then actually apply the labels.

I'm thinking that perhaps we can delegate this task to the PR author.

Currently we already utilize the PR template in CPython.

We can update the PR template to include metadata:

Needs backport to: 2.7 | 3.6 | 3.7

If we can let PR author to do their own research and determine where to backport to and give the above information, bedevere can then apply the necessary labels.

Core devs can still override that by removing the labels later on.