Update MSRV to 1.81 #624

Job	Run time
Clippy	52s
cargo-test (ubuntu-22.04, default, stable)	3m 20s
format	9s
cargo-test (macos-13, default, stable)	6m 15s
cargo-build (aarch64-linux-android, ubuntu-22.04)	2m 58s
cargo-test (windows-2019, default, stable)	7m 18s
cargo-build (armv7-linux-androideabi, ubuntu-22.04)	2m 57s
cargo-test (ubuntu-22.04, beta)	5m 51s
cargo-build (i686-linux-android, ubuntu-22.04)	2m 57s
cargo-test (ubuntu-22.04, blocking)	6m 6s
cargo-build (x86_64-linux-android, ubuntu-22.04)	2m 53s
cargo-test (ubuntu-22.04, blocking,beta)	6m 22s
cargo-build (x86_64-unknown-linux-musl, ubuntu-22.04)	2m 56s
cargo-test (ubuntu-22.04, tls-rustls --no-default-features)	5m 45s
cargo-test (ubuntu-22.04, tls-vendored-openssl --no-default-features)	6m 20s
cargo-build (aarch64-apple-ios, macos-13)	3m 12s
cargo-test (ubuntu-22.04, beta, default)	3m 19s
cargo-test (ubuntu-22.04, 1.75.0, default)	30s
	1h 10m 0s

Provide feedback