pmac

bump `digest`/`cipher` to `0.11.0-pre.8`/`0.5.0-pre.4` (#158) #288

Job	Run time
build (1.71.0, thumbv7em-none-eabi)	19s
minimal-versions	0s
build (1.71.0, wasm32-unknown-unknown)	16s
build (stable, thumbv7em-none-eabi)	9s
test (1.72.0)	32s
build (stable, wasm32-unknown-unknown)	1m 15s
test (stable)	10s
	2m 41s

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