fix(criterion): benchmark group generics breaking change

[art049]

• chore: add codspeed badges in sub readmes
• fix(criterion): add a default measurement to the benchmark group struct
• feat(criterion): support explicit lifetime for BenchmarkGroup

[codspeed-hq[bot]]

CodSpeed Performance Report

Merging #30 will not alter performance

_{Comparing fix/benchmark-group-generics (ca39531) with main (6064482)}

Summary

✅ 55 untouched benchmarks

🆕 2 new benchmarks

Benchmarks breakdown

	Benchmark	main	fix/benchmark-group-generics	Change
🆕	bench_explicit_measurement	N/A	0 s	N/A
🆕	bench_without_explicit_measurement	N/A	0 s	N/A