Add ARM support for GitHub actions

[bee-san]

https://docs.github.com/en/actions/writing-workflows/choosing-what-your-workflow-does/accessing-contextual-information-about-workflow-runs#runner-context

We should add arm support to our github actions.

here's one comment about it:

 FYI, I did start looking at this:

1. adding the appropriate build to the matrix and setting cross: true works perfectly!
2. …but then the Python tests fail for that step only.
3. it looks like actions-rs/toolchain is now deprecated and equally, it's not clear what the de facto standard Action might be.

So the build isn't too tricky but getting it working in a pipeline is proving a little more rabbit-hole-y than expected.

Originally posted by @PsypherPunk in #579 (comment)

[MRSKYWAY]

Convert current CI to use actions/setup-rust with a target matrix including aarch64-unknown-linux-gnu.
This will allow ARM builds to run in GitHub Actions.
I also propose using cross to simplify cross-compilation and running Python integration tests against the built ARM binaries.
We should install and configure Python dependencies explicitly in CI to address the current test failures on ARM.
Happy to prepare a PR if this direction sounds good!

[herbenderbler]

Hey RustScan friends! 👋 I noticed this issue among the good first issue list and thought I'd take a shot at it. I have a local branch testing new ARM builds, based on @MRSKYWAY's comment. As soon as I have builds and test all 🟢, I'll be sure to submit my PR for your review 😄