Bump `rand_core` to v0.10.0-rc-2 #358

Job	Run time
set-msrv / set-msrv	7s
minimal-versions	-1s
test (stable)	1m 1s
cross (powerpc-unknown-linux-gnu, 1.85.0)	1m 19s
no_std (stable, wasm32-unknown-unknown)	33s
cross (powerpc-unknown-linux-gnu, stable)	1m 16s
no_std (stable, thumbv7em-none-eabi)	29s
no_std (1.85.0, wasm32-unknown-unknown)	32s
test (1.85.0)	47s
no_std (1.85.0, thumbv7em-none-eabi)	34s
	6m 37s

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