Add Github Skyline endpoint as part of the github scraper

[nameisxi]

Skyline == github api for contribution activity (green boxes on the profile). Doesn't require authentication and not part of the core REST/GraphQL API - careful with call frequency to avoid getting blacklisted.

Examples:

• https://skyline.github.com/henrinikku/2022.json
• https://skyline.github.com/nameisxi/2022.json