CI: Use a Ubuntu 20.04 container to keep Ubuntu 20.04 support #1976

Job	Run time
sdist	35s
build-spidermonkey-unix (ubuntu-22.04, 3.10)	11s
build-spidermonkey-win	15s
build-spidermonkey-unix (ubuntu-22.04-arm, 3.10)	18s
build-spidermonkey-unix (macos-13, 3.10)	8s
build-spidermonkey-unix (macos-14, 3.10)	6s
build-and-test (ubuntu-22.04, 3.8)	4m 31s
build-and-test (ubuntu-22.04, 3.12)	3m 58s
build-and-test (ubuntu-22.04, 3.10)	3m 53s
build-and-test (ubuntu-22.04, 3.11)	4m 12s
build-and-test (macos-13, 3.10)	3m 49s
build-and-test (macos-13, 3.9)	3m 41s
build-and-test (ubuntu-22.04, 3.13)	3m 36s
build-and-test (macos-13, 3.12)	6s
build-and-test (macos-13, 3.8)	4m 44s
build-and-test (macos-13, 3.13)	1m 37s
build-and-test (macos-13, 3.11)	6m 13s
build-and-test (ubuntu-22.04, 3.9)	3m 49s
build-and-test (windows-2022, 3.11)	3m 55s
build-and-test (macos-14, 3.13)	3m 37s
build-and-test (macos-14, 3.8)	2m 53s
build-and-test (windows-2022, 3.9)	3m 48s
build-and-test (macos-14, 3.10)	3m 55s
build-and-test (windows-2022, 3.8)	7m 13s
build-and-test (windows-2022, 3.13)	7m 40s
build-and-test (windows-2022, 3.10)	5m 14s
build-and-test (ubuntu-22.04-arm, 3.9)	4m 4s
build-and-test (macos-14, 3.9)	1m 21s
build-and-test (ubuntu-22.04-arm, 3.8)	4m 24s
build-and-test (windows-2022, 3.12)	3m 42s
build-and-test (macos-14, 3.11)	2m 53s
build-and-test (macos-14, 3.12)	2m 57s
build-and-test (ubuntu-22.04-arm, 3.12)	4m 52s
build-and-test (ubuntu-22.04-arm, 3.13)	4m 52s
build-and-test (ubuntu-22.04-arm, 3.11)	4m 50s
build-and-test (ubuntu-22.04-arm, 3.10)	4m 1s
publish	1s
publish-nightly	1s
publish-archive	1s
	2h 1m 56s

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