Rust

Update fake requirement from 3.0 to 4.0 #158

Job	Run time
Lints	16s
Check (ubuntu-latest, stable)	12s
Test Suite (ubuntu-latest, stable)	35s
Check (ubuntu-latest, beta)	18s
Test Suite (ubuntu-latest, beta)	33s
Check (ubuntu-latest, nightly)	17s
Test Suite (ubuntu-latest, nightly)	30s
Check (macos-latest, stable)	27s
Test Suite (macos-latest, stable)	41s
Check (macos-latest, beta)	21s
Test Suite (macos-latest, beta)	43s
Check (macos-latest, nightly)	24s
Test Suite (macos-latest, nightly)	45s
Check (windows-latest, stable)	1m 38s
Test Suite (windows-latest, stable)	1m 43s
Check (windows-latest, beta)	49s
Test Suite (windows-latest, beta)	1m 18s
Test Suite (windows-latest, nightly)	1m 9s
Check (windows-latest, nightly)	54s
	13m 33s

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