Two new ideas on Stats and Dates

[VasilisZenergi]

Started using your action and I thought 2 new ideas would be really beneficial.

• You already display total number of PRs reviewed. Can we also display a %? That would be more valuable I think.
• Can we set an extra param apart from the period. Maybe a StartDate. So display all in the last X amount of days, but from that StartDate. So you may want to reset that period every quarter or once a year etc, while you still want to buffer the last 30 days since that StartDate.