[CI] Update to Swift 6 CI #30

Job	Run time
Swift 6 Language Mode	0s
Integration test / Linux (5.9)	1m 41s
Integration test / Linux (5.10)	1m 30s
Integration test / Linux (6.0)	1m 43s
Integration test / Linux (nightly-6.0)	2m 7s
Integration test / Linux (nightly-main)	33s
Soundness / Broken symlinks check	3s
Soundness / API breakage check	54s
Soundness / Documentation check	57s
Soundness / License headers check	3s
Soundness / Shell check	33s
Soundness / Unacceptable language check	6s
Unit tests / Unit tests / Linux (5.9)	48s
Unit tests / Unit tests / Linux (5.10)	44s
Unit tests / Unit tests / Linux (6.0)	56s
Unit tests / Unit tests / Linux (nightly-6.0)	1m 3s
Unit tests / Unit tests / Linux (nightly-main)	29s
Soundness / Python lint check	6s
Soundness / Format check	32s
Soundness / YAML lint check	4s
	14m 52s

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