ci: automated update to rustc 1.81.0 #6087

Job	Run time
Build and test (stable, true, --no-default-features)	1m 45s
Build and test (stable, true, --no-default-features)	3m 22s
Build Examples (example_cli)	14s
Build Examples (example_cli)	14s
Build and test (stable, true, --all-features)	1m 46s
Build and test (stable, true, --all-features)	3m 17s
Check no_std	25s
Check no_std	25s
Build Examples (example_bitcoind_rpc_polling)	25s
Build Examples (example_bitcoind_rpc_polling)	25s
Build and test (1.63.0, --no-default-features)	2m 15s
Build and test (1.63.0, --no-default-features)	4m 51s
Build Examples (example_electrum)	43s
Build Examples (example_electrum)	43s
Build and test (1.63.0, --all-features)	2m 23s
Build and test (1.63.0, --all-features)	4m 56s
Build Examples (example_esplora)	51s
Build Examples (example_esplora)	51s
Build Examples (wallet_electrum)	49s
Build Examples (wallet_electrum)	49s
Check WASM	35s
Check WASM	35s
Rust fmt	5s
Rust fmt	5s
Build Examples (wallet_esplora_async)	49s
Build Examples (wallet_esplora_async)	49s
Build Examples (wallet_esplora_blocking)	47s
Build Examples (wallet_esplora_blocking)	47s
prepare	4s
prepare	4s
Build Examples (wallet_rpc)	31s
Build Examples (wallet_rpc)	31s
clippy_check	3m 46s
clippy_check	3m 46s
	44m 43s

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