ci: pin cross and rust versions #412

Job	Run time
rustfmt	13m 55s
build / build (ubuntu-latest, x86_64, slight, v1)	38s
build-wasm-images / build_and_push (examples/spin-rust-hello, images/spin)	1m 34s
build / build (ubuntu-latest, x86_64, spin, v2)	54s
build-wasm-images / build_and_push (examples/spin-dotnet-hello, images/spin_dotnet)	1m 27s
build / build (ubuntu-latest, x86_64, wws, v1)	57s
build-wasm-images / build_and_push (examples/slight-rust-hello, images/slight)	4m 7s
build / build (ubuntu-latest, x86_64, lunatic, v1)	56s
build-wasm-images / build_and_push (examples/wws-js-hello, images/wws)	26s
build / build (ubuntu-latest, aarch64, slight, v1)	43s
build-wasm-images / build_and_push (examples/spin-inbound-redis, images/spin-inbound-redis)	1m 55s
build / build (ubuntu-latest, aarch64, spin, v2)	47s
build-wasm-images / build_and_push (examples/spin-outbound-redis, images/spin-outbound-redis)	1m 11s
build / build (ubuntu-latest, aarch64, wws, v1)	57s
build-wasm-images / build_and_push (examples/lunatic-rust-hello, images/lunatic)	47s
build / build (ubuntu-latest, aarch64, lunatic, v1)	48s
build-wasm-images / build_and_push (examples/lunatic-spawn, images/lunatic-spawn)	3m 4s
build-wasm-images / build_and_push (examples/lunatic-submillisecond, images/lunatic-submillisecond)	3m 5s
test	0s
	38m 11s

Provide feedback