update to opencv 4.12.0 #6

Job	Run time
setup	38s
windows (4.12.0, vs2022, 2022, v143)	7m 31s
windows (4.12.0, vs2019, 2022, v142)	7m 22s
devboard (licheerv-nano, true, riscv64-unknown-linux-musl.toolchain.cmake, wget -q https://occ-os...	4m 30s
devboard (avaota-f1, true, riscv32-linux-musl.toolchain.cmake, wget -q https://github.com/AvaotaS...	2m 32s
devboard (milkv-duo, true, riscv64-unknown-linux-musl.toolchain.cmake, wget -q https://occ-oss-pr...	4m 15s
	26m 48s

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