Drop Swift 5.9 #30

Job	Run time
Cxx interop / Construct Cxx interop matrix	3s
Unit tests / Construct unit test matrix	5s
Soundness / Broken symlinks check	3s
Soundness / Documentation check	2m 58s
Soundness / API breakage check	4m 48s
Soundness / Format check	35s
Soundness / License headers check	3s
Soundness / Unacceptable language check	4s
Soundness / Python lint check	4s
Soundness / Shell check	30s
Soundness / YAML lint check	3s
Cxx interop / Swift 6 language mode	2m 56s
Static SDK / Static SDK / Linux (latest-release Jammy)	3m 47s
Static SDK / Static SDK / Linux (main Jammy)	2m 1s
Cxx interop / Cxx interop / Linux (5.9)	29s
Cxx interop / Cxx interop / Linux (5.10)	2m 34s
Cxx interop / Cxx interop / Linux (6.0)	2m 58s
Cxx interop / Cxx interop / Linux (6.1)	2m 57s
Cxx interop / Cxx interop / Linux (nightly-next)	3m 47s
Cxx interop / Cxx interop / Linux (nightly-main)	1m 26s
Unit tests / Unit tests / Linux (5.9)	27s
Unit tests / Unit tests / Linux (5.10)	2m 39s
Unit tests / Unit tests / Linux (6.0)	2m 57s
Unit tests / Unit tests / Linux (6.1)	2m 56s
Unit tests / Unit tests / Linux (nightly-next)	3m 41s
Unit tests / Unit tests / Linux (nightly-main)	1m 23s
	46m 14s

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