Smarter pending check

[jenkoian]

There is a grace period of 1 week after the PR is merged, approved or attains the label hacktoberfest-accepted at the moment this is not factored into our pending check (we just do 1 week since PR was opened).

There is discussion on this here: #714

For github we should look at using the Graph API to inspect the events that have occurred on a PR. For gitlab we need to see if they offer anything similar.