ci: add behavior analysis of dependencies

[varunsh-coder]

This PR

1. Adds harden-runner GitHub Action to the test.yml workflow.
2. Sets the token permission for the workflow to contents: read. This is a security best practice and gets you are higher Scorecard score.

harden-runner GitHub Action detects hijacked dependencies and compromised build tools. It correlates outbound traffic with each step of the workflow so you can see what processes are calling what endpoints. This is the analysis when run on a fork: https://app.stepsecurity.io/github/varunsh-coder/karma/actions/runs/1923349069

You can also restrict traffic to the allowed endpoints for future runs. You do not need to grant any permission or install any App to use this, and the action (and agent the action uses) are open source.

Information on how harden-runner could have detected past package hijacks can be found here: https://github.com/step-security/supply-chain-goat. Do share feedback to improve the harden-runner GitHub Action developer experience. Thanks!