github/workflows: add auto labeler for PR

[raiden00pl]

Summary

This commit adds action for automatically labelling pull requests based on https://github.com/actions/labeler

Action configuration is located at .github/labeler.yml and can be expanded if needed.
At the moment only simple to check conditions are implemented, but the plugin allows to create more complex patterns.

Impact

Each new PR will be assigned a label according to the detected scope of changes.
Configured labels and patterns can be found in .github/labeler.yml and labels must mach labels in Github: https://github.com/apache/nuttx/labels

With this change we can better filter pull requests according to the changes made.

Another step to solve #13522

Testing

Tested on my private NuttX repo here: https://github.com/raiden00pl/nuttx/pulls

For NuttX repo it will look much nicer, I don't have set colors for labels in my repo.

There is no other method for testing this change.

[nuttxpr]

[Experimental Bot, please feedback here]

PR Requirements Review:

Verdict: The PR generally meets the NuttX requirements, but lacks some details for a comprehensive evaluation.

Strengths:

• Summary: Clearly outlines the purpose, functionality, and benefit of the change.
• Impact: Addresses most impact categories.
• Testing: Provides evidence of testing, but could be improved.

Areas for Improvement:

• Impact:
  • Impact on build: While you mention no build process changes, consider if any new dependencies are introduced by the action.
  • Security: Briefly address potential security implications of using third-party actions (e.g., access to repository data).
• Testing:
  • Build Hosts: Specify your local setup's OS, CPU, and compiler.
  • Targets: List the specific architectures and boards used for testing.
  • Testing Logs: The provided screenshot is helpful, but consider including relevant snippets from the action logs to showcase its functionality.
  • NuttX Repo Testing: Ideally, test the action directly on a fork/branch of the NuttX repo to demonstrate its behavior within the intended environment.

Recommendations:

1. Expand Impact Details: Provide specifics for build, security, and any other relevant categories.
2. Enhance Testing Section: Include detailed system information, action logs, and consider direct testing on a NuttX fork.

By addressing these points, you can enhance the clarity and completeness of your PR, making it easier for reviewers to assess and merge.