Update codecov/codecov-action action to v6 #6163

Job	Run time
Cache identify	5s
Shellcheck	7s
Dependency	6s
Prepare	7s
Ruff check and force	6s
Check commit	20s
Run pytest using Python 3.13	21s
Run pytest using Python 3.14	15s
Run mypy	16s
Process test coverage	12s
Process test complexity	6s
Build and publish Python 🐍 distributions 📦 to TestPyPI	12s
	2m 13s

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