Update rustls-platform-verifier requirement from 0.3 to 0.4 #552

Job	Run time
Check for documentation errors	19s
Build+test (stable, ubuntu-latest)	2m 44s
msrv	59s
Build+test (beta, ubuntu-latest)	2m 45s
Check semver compatibility	52s
Build+test (nightly, ubuntu-latest)	2m 38s
Clippy	58s
Build+test (macos-latest, stable)	2m 49s
Build+test (windows-latest, stable)	5m 42s
features	1m 39s
Format	12s
	21m 37s

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