DEV: Bump codecov/codecov-action from 3 to 4 (#2430) #4299

Job	Run time
Build & verify package	14s
pytest on windows	4m 53s
Check code style issues	47s
pytest on 3.7 (crypto-lib: cryptography)	3m 23s
pytest on 3.8 (crypto-lib: cryptography)	4m 50s
pytest on 3.9 (crypto-lib: cryptography)	4m 1s
pytest on 3.10 (crypto-lib: cryptography)	3m 28s
pytest on 3.11 (crypto-lib: cryptography)	3m 14s
pytest on 3.12 (crypto-lib: cryptography)	4m 41s
pytest on 3.7 (crypto-lib: pycryptodome)	3m 31s
pytest on 3.7 (crypto-lib: none)	4m 0s
Combine & check coverage.	13s
	37m 15s

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