Replace ENTRYPOINT by CMD in Docker image

[benoit74]

Rationale

Fix #28

Changed

• use CMD instead of ENTRYPOINT in Docker image
• force Python 3.11 (do not yet use Python 3.12)

[benoit74]

@rgaudin I would be happy to receive feedback on this, but I merge right now to move on, changes will probably be minor if you find some needed.

[rgaudin]

Looks good 👍