Add `linux-arm` to the default `RuntimeIdentifiers`

[alexrp]

Depends on: ziglang/zig#3287

It seems like arm-linux-gnueabihf means ARM v8 to Zig. We need a way to specify ARM v7 as that's what linux-arm means in .NET land. See: ziglang/zig#4911 (comment)

[alexrp]

There is a PR up to fix this in Zig so this might make 0.10.1?

[alexrp]

With ziglang/zig#12346 merged, we can probably do this when we switch to Zig 0.11.0 (see #46).