Bump `rand` for direct-minimal-versions compat (part 2; oops). #308

Job	Run time
no_std	26s
miri	1m 33s
build (ubuntu, stable, locked, true)	18m 15s
build (windows, stable, locked, false)	35m 7s
build (macos, stable, locked, false)	22m 19s
build (ubuntu, nightly, locked, false)	18m 29s
build (ubuntu, beta, locked, false)	17m 26s
build (ubuntu, stable, latest, false)	12m 19s
build (ubuntu, stable, minimal, false)	20m 50s
deploy	8s
features	23m 7s
fuzz	14m 28s
	3h 4m 27s

Provide feedback