Temporarily ban people that repeatedly open spammy PRs in a short window

[lee-dohm]

Many people who open spammy PRs open multiple PRs in succession. It would be nice if mistaken-pull-closer had the option to temporarily ban someone who opened a number of auto-closed PRs in a specified time period. A nice addition to this would be a warning one or two PRs before the block happens. Thoughts on defaults:

• Enabled: False
• Warning: 3
• Threshold: 5
• Window: 24 hours
• Block time: 3 days