Coverage: Implement fail_under #2306

Job	Run time
Run tests (3.10)	16s
Run tests (3.9.12)	16s
Run tests (3.12)	10s
Run tests (3.11.0)	18s
Run tests (3.10.4)	17s
Run tests (3.12.0)	19s
Run tests (3.11)	12s
Run tests (3.9)	9s
Run tests (3.13)	13s
Run tests (pypy3.9)	11s
Run tests (pypy3.10)	12s
Run tests (pypy3.11)	16s
Run tests (3.13.0)	16s
Run tests (3.14)	17s
Report coverage	16s
Create an issue if daily tests failed	0s
	3m 38s

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