Add the action for PR Metadata validation

[j-rivero]

🎉 New feature

Related and a resurrection of gazebo-tooling/release-tools#246. Follow up of #670

Summary

Second integration of the https://github.com/gazebo-tooling/pr-data-action/ into the main branch only of this repository. The github action added will check each of the PRs target to main for the presence of a changelog entry inside the .changelog directory following conventional commits.

Testing

Testing validation workflow iteratively by triggering different error states.

[github-actions]

❌ Changelog Validation Failed

The following issues were found with this PR:

• ❌ Missing changelog file
  • Please add a changelog file to the .changelog/ directory
  • Name it descriptively (e.g., fix-bug-123.md, add-new-feature.md)
  • The content must follow conventional commits format

Please fix the issues above and push your changes. The validation will run again automatically.

[github-actions]

❌ Changelog Validation Failed

The following issues were found with this PR:

• ✅ Changelog file found

• ❌ Invalid changelog content format - The changelog content must follow the Conventional Commits specification

Error:

Error: Missing commit type separator `:`

Caused by:
     --> 1:5
      |
    1 | This is not a conventional commit format
      |     ^---
      |
      = expected scope or type_separator

Valid format examples:

feat: add flying robot support
fix: fix a memory link in the walking algorithm

Please fix the issues above and push your changes. The validation will run again automatically.

[github-actions]

✅ Changelog Validation Passed

All required data for the changelog validation checks have passed:

• ✅ Changelog file found - Changes are documented
• ✅ Content format valid - Follows conventional commits specification

This PR is ready for review! 🚀