v3.1.1 release prep (#668) #681

Job	Run time
Check (x86_64-apple-darwin)	37s
Check (x86_64-unknown-linux-gnu)	45s
Clippy (x86_64-unknown-linux-gnu)	56s
Check lib (x86_64-unknown-linux-gnu)	26s
Check (x86_64-unknown-linux-musl)	38s
Clippy (aarch64-unknown-linux-gnu)	1m 44s
Check lib (aarch64-unknown-linux-gnu)	1m 11s
Check (x86_64-pc-windows-msvc)	3m 4s
Clippy (armv7-unknown-linux-gnueabihf)	1m 56s
Check lib (armv7-unknown-linux-gnueabihf)	1m 27s
Check (aarch64-unknown-linux-gnu)	1m 42s
Check (armv7-unknown-linux-gnueabihf)	1m 42s
Check lib MSRV (x86_64-unknown-linux-gnu)	34s
Rustfmt	16s
Check lib MSRV (aarch64-unknown-linux-gnu)	1m 16s
Unit Tests (x86_64-unknown-linux-gnu)	26s
Check lib MSRV (armv7-unknown-linux-gnueabihf)	1m 17s
Unit Tests (aarch64-unknown-linux-gnu)	1m 15s
Unit Tests (armv7-unknown-linux-gnueabihf)	1m 19s
	22m 31s

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