Add workflow to sync rush.json version on changes

[nev21]

This workflow automates the synchronization of rush.json version when changes are detected in package.json or rush.json. It includes steps for detecting changes, updating rush.json, running rush update, and committing the changes.

[Copilot]

Pull request overview

This PR introduces a GitHub Actions workflow that automates the synchronization of the rush.json version when Dependabot updates the @microsoft/rush package. The workflow detects Rush version changes, updates rush.json accordingly, runs rush update, and commits the changes back to the pull request.

Key Changes:

• New workflow triggered on pull requests that modify package.json, rush.json, or common-versions.json files
• Two-job pipeline: detection of Rush version changes and automated synchronization
• Automated commit process to keep rush.json in sync with package.json Rush version

---

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

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 100.00%. Comparing base (ae70e0d) to head (289ea73).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff            @@
##              main      #241   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files           26        26           
  Lines          458       458           
  Branches       113       113           
=========================================
  Hits           458       458           

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.