add aarch64 gnu and musl cross targets

[adamcstephens]

I get why you don't like working on this. :)

This will build tarballs for Linux aarch64 gnu and musl targets. I couldn't get the musl debs building because I wasn't sure how to provide the correct strip binary. Either way this still seems an improvement towards #200

Here's the error if you know a quick fix.

/home/runner/.cargo/bin/cargo deb --no-build --target=aarch64-unknown-linux-musl
strip: Unable to recognise the format of the input file `/home/runner/work/dust/dust/target/aarch64-unknown-linux-musl/release/dust'
cargo-deb: unable to strip binary '/home/runner/work/dust/dust/target/aarch64-unknown-linux-musl/release/dust': strip: exit status: 1.
hint: Target-specific strip commands are configured in [target.aarch64-unknown-linux-musl] strip = { path = "strip" } in .cargo/config

[adamcstephens]

Removed templating per docs

When you use expressions in an if conditional, you may omit the expression syntax (${{ }}) because GitHub automatically evaluates the if conditional as an expression.

[bootandy]

Thank you, I appreciate you looking at this,

I built an alpha release with the new builds here:
https://github.com/bootandy/dust/releases

[adamcstephens]

Just wanted to report that this has been working flawlessly for me across aarch64 and musl systems.

[bootandy]

thank you @adamcstephens