add `README.md` to interfaces #426

Job	Run time
build_linux (3.9)	3m 18s
build_linux (3.10)	2m 36s
build_linux (3.11)	2m 31s
build_linux (3.12)	2m 21s
build_windows (3.9)	9m 21s
build_windows (3.10)	13m 6s
build_windows (3.11)	12m 4s
build_windows (3.12)	12m 44s
test_linux (3.9, false, ubuntu-latest)	1m 48s
test_linux (3.10, false, ubuntu-latest)	1m 41s
test_linux (3.11, false, ubuntu-latest)	1m 46s
test_linux (3.12, false, ubuntu-latest)	1m 33s
test_windows (3.9, false, windows-2019)	3m 19s
test_windows (3.10, false, windows-2019)	3m 32s
test_windows (3.11, false, windows-2019)	3m 24s
test_windows (3.12, false, windows-2019)	3m 20s
	1h 18m 24s

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