Rust

Bump version to 20.3.4 #4765

Job	Run time
build-and-test (msrv)	14m 9s
build-and-test (latest)	13m 31s
fmt	9s
rust-analyzer-compat	3m 17s
publish-dry-run (macos-latest, aarch64-apple-darwin, --feature-powerset) / publish-dry-run	1m 7s
publish-dry-run (macos-latest, x86_64-apple-darwin, --feature-powerset) / publish-dry-run	1m 6s
publish-dry-run (ubuntu-latest, aarch64-unknown-linux-gnu, --feature-powerset) / publish-dry-run	46s
publish-dry-run (ubuntu-latest, x86_64-unknown-linux-gnu, --feature-powerset) / publish-dry-run	23s
publish-dry-run (windows-latest-8-cores, x86_64-pc-windows-msvc, --features opt --ignore-unknown-... / publish-dry-run	3m 39s
publish-dry-run (windows-latest-8-cores, x86_64-pc-windows-msvc) / publish-dry-run	3m 24s
complete	1s
	41m 32s

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