Set image name for y-provider in docker-compose.yml

[emersion]

Without this, Podman will not use the built image when starting the project.

[AntoLC]

LGTM!

Our commits must follow some rules, here some information about it: https://github.com/suitenumerique/docs/blob/main/CONTRIBUTING.md#commit-message-format

Contributors are required to sign off their commits with git commit --signoff: this confirms that they have read and accepted the Developer's Certificate of Origin 1.1. For security reasons we also require signing your commits with your SSH or GPG key with git commit -S.

Thank you for your contributions 🎉