Bump `crypto-bigint` to v0.6.0-rc.5 (#1078) #1391

Job	Run time
build (1.73.0, thumbv7em-none-eabi)	31s
build (1.73.0, wasm32-unknown-unknown)	30s
build (stable, thumbv7em-none-eabi)	24s
build (stable, wasm32-unknown-unknown)	23s
test (1.73.0)	33s
doc	45s
test (stable)	38s
	3m 44s

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