uucore: support cygwin #14121

Job	Run time
Pre-commit hooks	24s
Style/lint (windows-latest, feat_os_windows)	2m 6s
Style/lint (ubuntu-latest, all, true)	1m 31s
Style/Python	7s
Style/format (ubuntu-latest, feat_os_unix)	16s
Style/lint (macos-latest, feat_os_macos)	1m 22s
Style/spelling (ubuntu-latest, feat_os_unix)	16s
Style/toml	14s
	6m 16s

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