CI use 6.1 nightlies, enable more soundness #49

Job	Run time
Construct Cxx interop matrix	2s
Unit tests / Unit tests (swift:5.9-jammy, 5.9, true)	3m 21s
Unit tests / Unit tests (swift:5.10-jammy, 5.10, true)	3m 8s
Unit tests / Unit tests (swift:6.0-jammy, 6.0, true)	4m 59s
Unit tests / Unit tests (swiftlang/swift:nightly-6.1-jammy, nightly-6.1, true)	5m 21s
Unit tests / Unit tests (swiftlang/swift:nightly-main-jammy, nightly-main, true)	5m 13s
Soundness / API breakage check	1m 1s
Soundness / Unacceptable language check	4s
Soundness / Documentation check	1m 1s
Soundness / Broken symlinks check	5s
Soundness / Format check	38s
Soundness / Shell check	35s
Soundness / License headers check	6s
Soundness / YAML lint check	5s
Soundness / Python lint check	7s
Cxx interop / Linux (5.9)	1m 13s
Cxx interop / Linux (5.10)	1m 15s
Cxx interop / Linux (6.0)	1m 14s
Cxx interop / Linux (nightly-6.1)	1m 16s
Cxx interop / Linux (nightly-main)	1m 14s
	31m 58s

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