Potential fix for code scanning alert no. 4: Workflow does not contain permissions

[simongdavies]

Potential fix for https://github.com/hyperlight-dev/cargo-hyperlight/security/code-scanning/4

To fix the problem, the workflow should explicitly declare the minimum necessary permissions by adding a permissions block. Since none of the jobs require write access to repository contents, issues, or pull requests, setting permissions: contents: read at the workflow level (immediately under name: CI) covers all jobs while enforcing least privilege. This applies the restriction to all jobs unless a job-specific override is declared. The change should be made by inserting the following block at the top of the workflow file after the name key:

permissions:
  contents: read

No additional imports, methods, or definitions are needed. The fix can be implemented by adding these lines after line 3 and before on: (at line 5 as per the provided lines).

---

Suggested fixes powered by Copilot Autofix. Review carefully before merging.