Add Linux ARM support

[cretz]

Now that GitHub has Linux ARM runners available, setup-ruby now supports Linux ARM: ruby/setup-ruby#577. But when running oxidize-rb/actions/setup-ruby-and-rust@v1 on ubuntu-24.04-arm I get:

Error when downloading: key not found: "aarch64-unknown-linux-musl", retrying in 3 seconds...
Error when downloading: key not found: "aarch64-unknown-linux-musl", retrying in 3 seconds...
Error when downloading: key not found: "aarch64-unknown-linux-musl", retrying in 3 seconds...
/home/runner/work/_actions/oxidize-rb/actions/v1/cargo-binstall/cargo-binstall:56:in `fetch': key not found: "aarch64-unknown-linux-musl" (KeyError)
Did you mean?  "x86_64-unknown-linux-musl"

Presumably because Linux ARM is not available in

actions/cargo-binstall/cargo-binstall

Lines 10 to 15 in 841a470

	CHECKSUMS = {
	"x86_64-apple-darwin" => "71506ac1b15ed20a5f0b326d27883bed9d05d085c3b76a7828c9383636225dfe",
	"x86_64-unknown-linux-musl" => "d9f9876d9cc053827edb760775b9bacd091df70117c4d7f74b24f8f8749aa2b2",
	"x86_64-pc-windows-msvc" => "96f8325693ed00ccb96c7ae0d1da83e9c1c644d33d87175d4d4594f71246f283",
	"aarch64-apple-darwin" => "1cbc0ab3c12c3699379fb7f4640d194f71d4db2534d27b5c6849781920279721"
	}

. Can it be added? Unsure if it needs works with aarch64-unknown-linux-gnu and aarch64-unknown-linux-musl.

[stanhu]

I think this relates to oxidize-rb/rb-sys#493.

[ianks]

Yes this can be added, want to give it a whirl @cretz ?

[cretz]

It is low priority for me, but if I get some available time, sure! Don't let me hold it up if someone else needs it though.