Remove Ubuntu 20.04 from CI #42

Job	Run time
Event File	4s
Test macOS / Test (python-3.9, macos-15)	1m 4s
Test Ubuntu / Test (python-3.9, ubuntu-24.04)	13s
Test macOS / Test (python-3.10, macos-15)	1m 8s
Test Ubuntu / Test (python-3.10, ubuntu-24.04)	13s
Test macOS / Test (python-3.11, macos-15)	49s
Test Ubuntu / Test (python-3.11, ubuntu-24.04)	13s
Test macOS / Test (python-3.12, macos-15)	46s
Test Ubuntu / Test (python-3.12, ubuntu-24.04)	10s
Test macOS / Test (python-3.13, macos-15)	47s
Test Ubuntu / Test (python-3.13, ubuntu-24.04)	11s
Test macOS / Test (python-3.6, macos-13)	40s
Test Ubuntu / Test (python-3.8, ubuntu-22.04)	26s
Test macOS / Test (python-3.7, macos-13)	29s
Test Windows / Test (python-3.9, windows-2025)	23s
Test macOS / Test (python-3.8, macos-14)	3m 20s
Test Windows / Test (python-3.10, windows-2025)	25s
Test Windows / Test (python-3.11, windows-2025)	26s
Test Windows / Test (python-3.12, windows-2025)	26s
Test Windows / Test (python-3.13, windows-2025)	32s
Test Windows / Test (python-3.6, windows-2019)	1m 10s
Test Windows / Test (python-3.7, windows-2019)	1m 58s
Test Windows / Test (python-3.8, windows-2022)	39s
Coverage & Lint	11s
Publish Package	15s
Test whl / Test whl (python-3.9, ubuntu-24.04)	5s
Test whl / Test whl (python-3.10, ubuntu-24.04)	6s
Test whl / Test whl (python-3.11, ubuntu-24.04)	5s
Test whl / Test whl (python-3.12, ubuntu-24.04)	4s
Test whl / Test whl (python-3.13, ubuntu-24.04)	9s
Test whl / Test whl (python-3.8, ubuntu-22.04)	5s
	17m 32s

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