chacha20: bump `rand_core` to v0.9 (#385) #621

Job	Run time
build (1.81.0, thumbv7em-none-eabi)	18s
test (1.81.0)	16s
build (1.81.0, wasm32-unknown-unknown)	17s
test (stable)	13s
build (stable, thumbv7em-none-eabi)	10s
build (stable, wasm32-unknown-unknown)	10s
minimal-versions / minimal-versions	24s
	1m 48s

Provide feedback