Bump mypy from 1.8.0 to 1.9.0 #120

Job	Run time
tests (windows, 3.11, true, true) / tests	4m 50s
tests (ubuntu, pypy3.10, false, false) / tests	2m 6s
tests (ubuntu, 3.10, false, false) / tests	1m 1s
tests (macos, 3.10, true, false) / tests	3m 52s
	11m 49s

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