fix: modify step 3 grading to check for changed files instead of specific keywords

[FidelusAleksander]

Summary

This is a long needed update to be less strict on step 3 grading where we checked for specific keywords. Users reported that copilot sometimes did the adequate changes but did not use the participant keyword

Test run issue: FidelusAleksander/skills-getting-started-with-github-copilot-step-3-grading#1

Changes

The grading now only checks if both files were changed compared to the main branch

Closes: #111

Copilot summary

This pull request updates the workflow in .github/workflows/3-copilot-edits.yml to improve how it checks for modifications to app.js and styles.css as part of a practical exercise. The main changes include switching from keyphrase-based checks to verifying that the files were actually modified, and updating the step descriptions accordingly.

Workflow improvements for file modification checks:

• Replaced the previous keyphrase-based checks (using skills/action-keyphrase-checker) with explicit checks that confirm whether src/static/app.js and src/static/styles.css were modified, using tj-actions/changed-files and actions/github-script. This ensures that participants actually edit the required files.
• Updated the step descriptions in the results table to clarify that the workflow now checks if the files were modified, rather than searching for specific content.

Task list

• For workflow changes, I have verified the Actions workflows function as expected.
• For content changes, I have reviewed the style guide.

[Copilot]

Pull request overview

This PR updates the grading mechanism for step 3 to check if files were modified rather than searching for specific keywords. The change addresses user reports where Copilot made adequate changes without using the required "participant" keyword.

Key Changes:

• Replaced keyword-based validation with file modification detection
• Added tj-actions/changed-files@v47 action to detect changed files
• Updated validation logic to check if app.js and styles.css were modified compared to the main branch

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[arilivigni]

In general can't you check for the files and a word that is consistent instead of making these changes?

Does this add additional actions from the marketplace that we haven't used before? KISS 😄

[chriswblake]

Looks good to me. Thanks for attaching the test run.
I would fix the embedded variable. Shouldn't be a problem here, but better safe than sorry.

[FidelusAleksander]

In general can't you check for the files and a word that is consistent instead of making these changes?

Does this add additional actions from the marketplace that we haven't used before? KISS 😄

Hey that's what was the original approach - to check for participant keyword and it works in most cases, but because we have no way of telling what Copilot is going to generate this led to issues being reported.

Like this one #25
and more recently #111

Now the steps will pass more gracefully with any changes to these files. I believe we also use tj-actions/changed-files in one or a few other exercises for grading