🦥 Document how to get `geol` in a Github Codespace

[adriens]

❔ About

Some people may find useful to use geol in GH Codespace so they can play with it in a very cumfortable way.

Therefore, documenting how to get the thing done will be very useful.

📑 Related issues

• 🐳 Deliver as a OCI Image : dockerhub et ghcr #28