CI: Use a Ubuntu 20.04 container to keep Ubuntu 20.04 support #1973

Job	Run time
sdist	30s
build-spidermonkey-unix (macos-13, 3.10)	10s
build-spidermonkey-unix (macos-14, 3.10)	6s
build-spidermonkey-unix (ubuntu-22.04, 3.10)	9s
build-spidermonkey-unix (ubuntu-22.04-arm, 3.10)	18s
build-spidermonkey-win	11s
build-and-test (ubuntu-22.04, 3.10)	4m 47s
build-and-test (ubuntu-22.04, 3.11)	4m 23s
build-and-test (ubuntu-22.04, 3.8)	4m 5s
build-and-test (ubuntu-22.04, 3.9)	4m 4s
build-and-test (macos-13, 3.10)	4m 48s
build-and-test (ubuntu-22.04, 3.12)	5m 4s
build-and-test (macos-13, 3.11)	5s
build-and-test (macos-13, 3.8)	3m 58s
build-and-test (macos-13, 3.9)	5m 31s
build-and-test (macos-13, 3.12)	4m 17s
build-and-test (macos-14, 3.8)	2m 52s
build-and-test (ubuntu-22.04, 3.13)	4m 14s
build-and-test (macos-14, 3.13)	2m 42s
build-and-test (macos-14, 3.12)	2m 58s
build-and-test (windows-2022, 3.9)	6m 52s
build-and-test (windows-2022, 3.10)	7m 23s
build-and-test (windows-2022, 3.11)	7m 2s
build-and-test (windows-2022, 3.8)	6m 51s
build-and-test (macos-13, 3.13)	7m 44s
build-and-test (macos-14, 3.10)	52s
build-and-test (macos-14, 3.9)	2m 11s
build-and-test (windows-2022, 3.12)	7m 24s
build-and-test (ubuntu-22.04-arm, 3.12)	4m 2s
build-and-test (ubuntu-22.04-arm, 3.10)	3m 37s
build-and-test (ubuntu-22.04-arm, 3.8)	3m 30s
build-and-test (macos-14, 3.11)	1s
build-and-test (ubuntu-22.04-arm, 3.11)	4m 1s
build-and-test (ubuntu-22.04-arm, 3.9)	4m 1s
build-and-test (windows-2022, 3.13)	7m 30s
build-and-test (ubuntu-22.04-arm, 3.13)	3m 36s
publish-nightly	1s
publish-archive	1s
publish	1s
	2h 11m 52s

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