Add a check for dependabot PR updating guest or common lib dependencies

[simongdavies]

We have a check in the PR workflow to ensure that Cargo.lock files are up to date as a part of any PR. This works fine for most scenarios but when dependabot updates depdendencies in either hyperlight_common or hyperlight_guest this may make the Cargo.lock file out of date for the simpleguest and callbackguest test guest binaries.

See #148 for an example of this.

This PR updates the PR workflow to update those files if there are dependabot changes to the dependencies in either of those crates.

[ludfjig]

I suspect if we add the directory of simpleguest to dependabot.yml, it would update those cargo.toml as well, and we should be fine. It might be an easier solution that this. I'm thinking replace

  - package-ecosystem: "cargo"
    directory: "/"
    schedule:
      interval: "daily"

with

  - package-ecosystem: "cargo"
    directory: ["/", "src/tests/rust_guests/simpleguest"]
    schedule:
      interval: "daily"

https://docs.github.com/en/code-security/dependabot/working-with-dependabot/dependabot-options-reference#directories-or-directory--

It might be worth a try anyway?

[simongdavies]

It might be worth a try anyway?

Yes , definitely, I will close this one and open a new one with your suggestion, if it doesnt work we can aways re-open this