[pyproject.toml] Use relative_files option for coverage to avoid long names in...

[pyproject.toml] Use relative_files option for coverage to avoid long names in CI-generated coverage reports
4 jobs for coverage-uses-relative-files in 28 minutes and 14 seconds (queued for 3 seconds)
Status Name Job ID Coverage
  Build
passed build_linux_37 #243693
docker

00:27:37

68.0%
passed build_linux_38 #243694
docker

00:26:47

69.0%
passed build_macos_intel_37 #243691
macos intel

00:28:08

68.0%
passed build_macos_intel_38 #243692
macos intel

00:26:31

69.0%