Bump xunit.v3 to 2.0.0 #502

Job	Run time
build (ubuntu-latest, Debug)	2m 2s
build (windows-latest, Release)	5m 40s
build (windows-latest, Debug)	4m 34s
build (ubuntu-latest, Release)	2m 5s
build (macos-latest, Debug)	1m 12s
build (macos-latest, Release)	1m 3s
publish-coverage / publish-coverage	37s
	17m 13s

Provide feedback