Bump `cipher` to v0.5.0-pre.6; `digest` to v0.11.0-pre.9 #302

Job	Run time
build (1.72.0, thumbv7em-none-eabi)	16s
build (1.72.0, wasm32-unknown-unknown)	16s
build (stable, thumbv7em-none-eabi)	17s
build (stable, wasm32-unknown-unknown)	18s
test (1.72.0)	24s
test (stable)	20s
minimal-versions / minimal-versions	39s
	2m 30s

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