Switch to codecov #6

Job	Run time
black	10s
minimal	1m 6s
coverage	2m 33s
notebooks	20m 4s
black_fix	0s
pip_check	47s
unittest_abinit	1m 26s
unittest_gpaw	12m 19s
unittest_mace	2m 23s
unittest_matgl	2m 15s
unittest_matrix (macos-latest, 3.12)	3m 59s
unittest_old	2m 49s
unittest_matrix (ubuntu-latest, 3.12)	2m 18s
unittest_qe	8m 42s
unittest_matrix (windows-latest, 3.12)	4m 31s
unittest_siesta	1m 39s
unittest_matrix (ubuntu-latest, 3.11)	2m 14s
unittest_matrix (ubuntu-latest, 3.10)	2m 18s
autobot	0s
	1h 11m 33s

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