ci: update rust to 1.81 #1415

Job	Run time
tests (vmm/sandbox, --all-features)	3m 48s
checks (vmm/sandbox, --all-features)	1m 30s
tests (vmm/task, --all-features)	3m 13s
checks (vmm/task, --all-features)	1m 28s
tests (shim, --all-features)	2m 32s
checks (shim, --all-features)	1m 13s
tests (quark, --all-features)	2m 25s
checks (quark, --all-features)	1m 16s
tests (runc, --all-features)	2m 59s
checks (runc, --all-features)	1m 29s
tests (wasm, --features=wasmedge, 0.13.5)	3m 15s
checks (wasm, --features=wasmedge, 0.13.5)	1m 28s
tests (wasm, --features=wasmtime)	3m 39s
checks (wasm, --features="wasmedge, wasmedge_wasi_nn", 0.13.5)	1m 29s
checks (wasm, --features=wasmtime)	1m 27s
	33m 11s

Provide feedback