Reset approve for pull-request after changes in branch before merge pull-request

After a pull-request has been approved, it wasn't merged at the same moment, because we have two persons, who must approve a pull-request before it will be merged.
After the first person approval, the author of the request is able to push new commits which can considerably change the previously approved code. The author can push to the approved request either because of new bugs found by the second code-reviewer, or by any other reason.

Our strongly desired suggestion is to reset the approved state of the request if any new pushes are made to this request.