Migrate CI to use GitHub Actions. #1

Job	Run time
Swift 6 Language Mode	0s
Soundness / Unacceptable language check	3s
Soundness / API breakage check	2m 14s
Soundness / Documentation check	1m 53s
Soundness / License headers check	3s
Soundness / Broken symlinks check	5s
Soundness / Format check	37s
Soundness / Shell check	38s
Soundness / Python lint check	4s
Soundness / YAML lint check	10s
Cxx interop / Cxx interop / Linux (5.9)	1m 24s
Cxx interop / Cxx interop / Windows (6.0)	3s
Cxx interop / Cxx interop / Linux (5.10)	1m 22s
Cxx interop / Cxx interop / Windows (nightly-6.0)	3s
Cxx interop / Cxx interop / Windows (nightly-main)	1s
Cxx interop / Cxx interop / Linux (6.0)	1m 29s
Cxx interop / Cxx interop / Linux (nightly-6.0)	1m 53s
Cxx interop / Cxx interop / Linux (nightly-main)	1m 41s
Unit tests / Unit tests / Linux (5.9)	2m 50s
Unit tests / Unit tests / Windows (6.0)	2s
Unit tests / Unit tests / Linux (5.10)	2m 45s
Unit tests / Unit tests / Windows (nightly-6.0)	1s
Unit tests / Unit tests / Linux (6.0)	2m 54s
Unit tests / Unit tests / Windows (nightly-main)	3s
Unit tests / Unit tests / Linux (nightly-6.0)	3m 19s
Unit tests / Unit tests / Linux (nightly-main)	3m 15s
	28m 52s

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