chore: Remove trending repository fetch workflow and scripts

This commit removes the GitHub Actions workflow and associated Python scripts previously used for fetching and caching trending repositories.

- Deleted the `.github/workflows/fetch-trending-repos.yml` workflow file, which was responsible for periodically running the fetch script.
- Deleted the `scripts/fetch_trending.py` script that contained the logic for querying the GitHub API to find trending repositories for different platforms (Android, Windows, macOS, Linux).
- Deleted the `scripts/requirements.txt` file, which only contained the `requests` dependency for the removed script.

Author: rainxchzed