Use async-limiter utilization metrics

[samuel-williams-shopify]

Summary

• Require async-limiter v2.2 and async-utilization v0.4.
• Wire Falcon connection limiters to the socket_accept utilization namespace.
• Wire long task limiters to the long_task utilization namespace.
• Add release notes and coverage for the namespaced metrics.

Validation

• COVERAGE=PartialSummary bundle exec sus
• COVERAGE=PartialSummary bundle exec bake covered:validate --paths .covered.db \;
• bundle exec rubocop
• bundle exec bake decode:index:coverage lib