loongarch64 support

[mcandre]

Checklist

• [X] I've looked through the issues and pull requests for similar request
• [ ] This feature could be solved with a custom docker image (optional)

Describe your request

Since 1.74.0, Rust has added loongarch64-unknown-linux-gnu as a tier 2 level target.

https://doc.rust-lang.org/nightly/releases.html#version-1710-2023-07-13

Can we please get a first (or third) party cross image published for generating loongarch64-unknown-linux-gnu application binaries?

Describe why this would be a good inclusion for cross

Complete the span of available Rust targets more fully, so that Rust application developers can more easily support diverse platforms.