Bump MSRV to 1.81 (#631) #105

Job	Run time
minimal-versions	0s
set-msrv / set-msrv	5s
windows (x86_64-pc-windows-gnu, 1.81.0)	1m 19s
build (1.81.0, thumbv7em-none-eabi)	23s
windows (x86_64-pc-windows-gnu, stable)	1m 9s
linux (x86_64-unknown-linux-gnu, 1.81.0)	32s
build (1.81.0, wasm32-unknown-unknown)	21s
cross (1.81.0, aarch64-unknown-linux-gnu, default)	39s
linux (x86_64-unknown-linux-gnu, stable)	26s
build (1.81.0, loongarch64-unknown-linux-gnu)	19s
cross (1.81.0, powerpc-unknown-linux-gnu, default)	41s
build (stable, thumbv7em-none-eabi)	28s
cross (stable, aarch64-unknown-linux-gnu, default)	37s
macos (1.81.0)	26s
build (stable, wasm32-unknown-unknown)	13s
cross (stable, powerpc-unknown-linux-gnu, default)	38s
macos (stable)	23s
build (stable, loongarch64-unknown-linux-gnu)	25s
	9m 4s

Provide feedback