CI use 6.1 nightlies, enable more soundness #50

Job	Run time
Construct Cxx interop matrix	3s
Unit tests / Unit tests (swift:5.9-jammy, 5.9, true)	4m 23s
Unit tests / Unit tests (swift:5.10-jammy, 5.10, true)	2m 58s
Unit tests / Unit tests (swift:6.0-jammy, 6.0, true)	3m 42s
Unit tests / Unit tests (swiftlang/swift:nightly-6.1-jammy, nightly-6.1, true)	5m 18s
Unit tests / Unit tests (swiftlang/swift:nightly-main-jammy, nightly-main, true)	3m 58s
Soundness / API breakage check	3m 28s
Soundness / Documentation check	2m 29s
Soundness / Unacceptable language check	8s
Soundness / License headers check	5s
Soundness / Broken symlinks check	4s
Soundness / Format check	37s
Soundness / Shell check	38s
Soundness / YAML lint check	4s
Soundness / Python lint check	9s
Cxx interop / Linux (5.9)	1m 55s
Cxx interop / Linux (5.10)	1m 51s
Cxx interop / Linux (6.0)	2m 13s
Cxx interop / Linux (nightly-6.1)	2m 42s
Cxx interop / Linux (nightly-main)	2m 48s
	39m 33s

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