ci: dynamic repository matrix generation for contributor metrics

[Rucha0901]

Pull Request: Dynamic Repository Matrix Generation for Contributor Metrics CI

Summary of Changes

• Dynamic Repository Discovery Script (.github/scripts/fetch_active_repos.py):

  • Implemented Python script querying GitHub REST API (/orgs/flatcar/repos) with pagination to dynamically list all active, non-archived, and non-fork repositories.
  • Added robust fallback mechanism parsing MAINTAINERS.md if API calls fail or return no results.
  • Exports discovery results to $GITHUB_ENV (REPOSITORIES=flatcar/repo1,flatcar/repo2,...).

• Unit Tests (.github/scripts/test_fetch_active_repos.py):

  • Created unit tests covering API pagination, filter logic (excluding archived & forks), fallback parsing of MAINTAINERS.md, and $GITHUB_ENV export.

• Workflow Enhancements (.github/workflows/issue-pr-contrib-metrics.yaml):

  • Added Fetch active repositories pre-step using .github/scripts/fetch_active_repos.py.
  • Replaced hardcoded repository string at line 55 with ${{ env.REPOSITORIES }}.
  • Fixed ShellCheck SC2129 warning by grouping summary_report.md and comment_report.md redirections into block redirects.

• CI & Verification (.github/workflows/contrib-metrics-test.yml):

  • Added GitHub Actions workflow incorporating actionlint to automatically check syntax and lint errors across all workflow files.
  • Included Python unit test discovery for .github/scripts/.

Verification Evidence

• Executed python3 -m unittest discover -s .github/scripts -v (4/4 tests passed).
• Executed actionlint .github/workflows/*.yaml .github/workflows/*.yml (0 syntax errors / warnings).
• Executed python3 .github/scripts/fetch_active_repos.py against live GitHub API (discovered 53 active repositories).

Signed-off-by: Rucha0901 imt_2025071@iiitm.ac.in

[sayanchowdhury]

Hi @Rucha0901, thanks for opening this PR!

A couple of questions before we dig into review - it's pretty challenging to read through the description.

1. Did you use any AI tools to help write this contribution?

2. What is your motivation for the fix or what issue are you trying to resolve?