Gather Lotus maintainer PR review Stats

We would like to track PR request stats metrics (i.e: how often eacch team members :eyes: PRs and whats sthe overall team velocity . i found this t ooling that should give us enough data to start with https://github.com/marketplace/actions/pull-request-stats.

Goal is to install this for lotus repo with [slack channel integration](https://github.com/flowwer-dev/pull-request-stats/blob/master/docs/slack.md) to send weekly summary in #fil-lotus-dev channel