Upgrade dev-dependency `itertools` to 0.14 #437

Job	Run time
Check MSRV and minimal-versions	43s
miri	4m 55s
nostd_build (1.63.0, thumbv6m-none-eabi)	23s
clippy	16s
nostd_build (stable, thumbv6m-none-eabi)	15s
tests (1.63.0)	59s
tests (stable, arbitrary)	40s
tests (stable, quickcheck)	43s
tests (stable, rayon)	47s
tests (stable, rustc-rayon)	46s
tests (stable, serde)	49s
tests (stable, borsh)	37s
tests (stable, std)	37s
tests (beta)	38s
tests (nightly, test build benchmarks)	35s
Success	1s
	13m 44s

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