.github/workflows: Update coverage upload step. #1738

Job	Run time
Run benchmarks	1m 35s
Check relative links in website	30s
Run checks	49s
Run tests (emulated riscv64)	1m 20s
Run tests (emulated s390x)	1m 15s
Run tests (ubuntu, 1.23.x)	1m 46s
Run tests (macos, 1.23.x)	1m 5s
Run tests (windows, 1.23.x)	2m 7s
Run tests (ubuntu, 1.22.x)	32s
Upload test coverage (linux)	13s
Upload test coverage (macos)	13s
Upload test coverage (windows)	8s
	11m 33s

Provide feedback