Enable Swift 6.1 jobs in CI #28

Job	Run time
Cxx interop / Construct Cxx interop matrix	5s
Unit tests / Construct unit test matrix	3s
Soundness / API breakage check	4m 26s
Soundness / Broken symlinks check	5s
Soundness / Documentation check	2m 54s
Soundness / Format check	31s
Soundness / License headers check	3s
Soundness / Unacceptable language check	2s
Soundness / Python lint check	5s
Soundness / Shell check	32s
Soundness / YAML lint check	2s
Cxx interop / Swift 6 language mode	2m 34s
Static SDK / Static SDK / Linux (latest-release Jammy)	3m 36s
Static SDK / Static SDK / Linux (main Jammy)	4m 28s
Unit tests / Unit tests / Linux (5.9)	2m 21s
Unit tests / Unit tests / Linux (5.10)	2m 20s
Unit tests / Unit tests / Linux (6.0)	2m 52s
Unit tests / Unit tests / Linux (6.1)	2m 42s
Unit tests / Unit tests / Linux (nightly-next)	3m 24s
Unit tests / Unit tests / Linux (nightly-main)	3m 27s
Cxx interop / Cxx interop / Linux (5.9)	2m 39s
Cxx interop / Cxx interop / Linux (5.10)	2m 26s
Cxx interop / Cxx interop / Linux (6.0)	2m 53s
Cxx interop / Cxx interop / Linux (6.1)	2m 56s
Cxx interop / Cxx interop / Linux (nightly-next)	3m 30s
Cxx interop / Cxx interop / Linux (nightly-main)	3m 27s
	54m 23s

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