Align 0.5 roadmap with feature admission gate #47

Job	Run time
Miri	2m 3s
Format, lint, test, and audit	50s
Platform tests (windows-latest)	37s
Platform tests (macos-latest)	28s
Platform tests (ubuntu-latest)	19s
no_std target build (x86_64-unknown-linux-gnu)	15s
no_std target build (thumbv7em-none-eabihf)	16s
no_std target build (aarch64-unknown-linux-gnu)	17s
no_std target build (wasm32-unknown-unknown)	18s
no_std target build (x86_64-unknown-freebsd)	20s
	5m 43s

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