Migrate to Rust 2021 (#160) #634

Job	Run time
cross (ubuntu-latest)	2m 32s
msrv (ubuntu-latest, 1.63)	1m 19s
cross (macos-latest)	42s
windows_gnu (nightly, x86_64-pc-windows-gnu)	2m 14s
msrv (windows-latest, 1.63)	1m 51s
test (ubuntu-latest, nightly)	1m 17s
clippy	38s
test (ubuntu-latest, beta)	1m 5s
security_audit	8s
fmt	15s
test (ubuntu-latest, stable)	1m 24s
test (windows-latest, nightly)	1m 56s
test (windows-latest, beta)	1m 45s
test (windows-latest, stable)	2m 17s
test (macos-latest, nightly)	1m 49s
test (macos-latest, beta)	1m 4s
test (macos-latest, stable)	1m 45s
	24m 1s

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