Bump `cipher` to v0.5.0-pre.6 (#430) #1042

Job	Run time
aesni (i686-unknown-linux-gnu, 1.72.0, sudo apt update && sudo apt install gcc-multilib)	37s
aesni (i686-unknown-linux-gnu, stable, sudo apt update && sudo apt install gcc-multilib)	32s
armv8 (aarch64-unknown-linux-gnu, 1.72.0)	43s
autodetect (i686-unknown-linux-gnu, 1.72.0, sudo apt update && sudo apt install gcc-multilib)	37s
aesni (x86_64-unknown-linux-gnu, 1.72.0)	32s
build (1.72.0, thumbv7em-none-eabi)	29s
autodetect (i686-unknown-linux-gnu, stable, sudo apt update && sudo apt install gcc-multilib)	37s
aesni (x86_64-unknown-linux-gnu, stable)	19s
clippy	15s
autodetect (x86_64-unknown-linux-gnu, 1.72.0)	20s
build (1.72.0, wasm32-unknown-unknown)	25s
build (stable, thumbv7em-none-eabi)	29s
autodetect (x86_64-unknown-linux-gnu, stable)	21s
build (stable, wasm32-unknown-unknown)	26s
cross (aarch64-unknown-linux-gnu, 1.72.0)	1m 8s
cross (aarch64-unknown-linux-gnu, stable)	1m 9s
soft (i686-unknown-linux-gnu, 1.72.0, sudo apt update && sudo apt install gcc-multilib)	30s
cross (powerpc-unknown-linux-gnu, 1.72.0)	1m 9s
soft (i686-unknown-linux-gnu, stable, sudo apt update && sudo apt install gcc-multilib)	30s
cross (powerpc-unknown-linux-gnu, stable)	1m 6s
soft (x86_64-unknown-linux-gnu, 1.72.0)	22s
soft (x86_64-unknown-linux-gnu, stable)	16s
minimal-versions / minimal-versions	25s
	13m 17s

Provide feedback