Rust

Update Rust crate log to 0.4.21 #536

Job	Run time
build-unix (1.63, ubuntu)	3m 25s
build-unix (1.63, macos)	4m 56s
build-windows (i686, msvc, 1.63)	4m 5s
build-docker (1.63, x86_64-unknown-freebsd)	1m 39s
build-unix (stable, ubuntu)	39s
build-windows (i686, msvc, stable)	2m 35s
build-unix (stable, macos)	46s
build-windows (i686, msvc, nightly)	1m 7s
build-docker (stable, x86_64-unknown-freebsd)	1m 35s
build-unix (nightly, ubuntu)	32s
build-docker (nightly, x86_64-unknown-freebsd)	1m 51s
build-windows (x86_64, msvc, 1.63)	4m 3s
build-unix (nightly, macos)	1m 8s
build-windows (x86_64, msvc, stable)	1m 18s
build-windows (x86_64, msvc, nightly)	57s
build-windows (aarch64, msvc, 1.63)	4m 21s
build-windows (aarch64, msvc, stable)	1m 28s
build-windows (aarch64, msvc, nightly)	49s
	37m 14s

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