[CI] Update to Swift 6 CI #134

Job	Run time
Compatibility test	5m 1s
Swift 6 Language Mode	0s
Example packages / Linux (5.9)	16m 37s
Example packages / Linux (5.10)	15m 38s
Example packages / Linux (6.0)	17m 16s
Example packages / Linux (nightly-6.0)	21m 57s
Example packages / Linux (nightly-main)	28s
Integration test / Linux (5.9)	1m 39s
Soundness / API breakage check	0s
Integration test / Linux (5.10)	1m 41s
Integration test / Linux (6.0)	1m 51s
Soundness / Broken symlinks check	5s
Integration test / Linux (nightly-6.0)	2m 12s
Soundness / Documentation check	1m 38s
Integration test / Linux (nightly-main)	28s
Soundness / Format check	40s
Soundness / License headers check	6s
Soundness / Shell check	38s
Soundness / Unacceptable language check	3s
Soundness / Python lint check	4s
Soundness / YAML lint check	0s
Unit tests / Unit tests / Linux (5.9)	1m 39s
Unit tests / Unit tests / Linux (5.10)	1m 43s
Unit tests / Unit tests / Linux (6.0)	1m 48s
Unit tests / Unit tests / Linux (nightly-6.0)	2m 10s
Unit tests / Unit tests / Linux (nightly-main)	29s
	1h 35m 51s

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