ci-testing.yml Windows-friendly ENV variables

[glenn-jocher]

Per https://docs.github.com/en/actions/using-workflows/workflow-syntax-for-github-actions

🛠️ PR Summary

_{Made with ❤️ by Ultralytics Actions}

🌟 Summary

Improvement of CI environment variable display in GitHub Actions workflow.

📊 Key Changes

• Modified the GitHub Actions CI testing workflow file to display environment variables using the GitHub context syntax ${{ }}.
• Updated the following environment variables: RUNNER_OS, GITHUB_EVENT_NAME, GITHUB_WORKFLOW, GITHUB_ACTOR, GITHUB_REPOSITORY, GITHUB_REPOSITORY_OWNER.

🎯 Purpose & Impact

• Purpose: The update ensures that environment variables are being correctly referenced and displayed within the CI (continuous integration) testing process.
• Impact: Provides more robust and reliable debugging information for maintainers. Enhances the readability of the CI logs for developers and contributors, making it easier to monitor the CI workflow and diagnose issues if they arise. 🛠️🔍