sha2

[WIP] MD6 implementation #983

Job	Run time
loongarch64_asm	22s
test-msrv	11s
minimal-versions / minimal-versions	3m 49s
set-msrv / set-msrv	5s
build (1.59, thumbv7em-none-eabi)	4m 3s
linux (i686-unknown-linux-gnu, 1.59.0, sudo apt update && sudo apt install gcc-multilib)	4m 26s
build (1.59, wasm32-unknown-unknown)	4m 6s
linux (i686-unknown-linux-gnu, stable, sudo apt update && sudo apt install gcc-multilib)	3m 14s
macos (1.59.0)	7m 17s
build (stable, thumbv7em-none-eabi)	27s
linux (x86_64-unknown-linux-gnu, 1.59.0)	4m 2s
cross (1.59.0, aarch64-unknown-linux-gnu, default)	4m 10s
macos (stable)	1m 19s
build (stable, wasm32-unknown-unknown)	27s
linux (x86_64-unknown-linux-gnu, stable)	2m 47s
cross (1.59.0, powerpc-unknown-linux-gnu, default)	4m 26s
cross (stable, aarch64-unknown-linux-gnu, default)	42s
windows (1.59.0, x86_64-pc-windows-gnu)	5m 28s
cross (stable, powerpc-unknown-linux-gnu, default)	36s
windows (stable, x86_64-pc-windows-gnu)	1m 19s
cross (stable, aarch64-unknown-linux-gnu, asm)	51s
	54m 7s

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