Feature/update release cd

[vincentbrison]

There is no proper way to trigger an action on a specific pull request merge (or it is hacky at the moment).
Maybe it will be available later, but for now, we can trigger the full release flow using a version tag.

The release flow would look like that:

• Create a release branch, where the CI will commit changelog and images descriptions.
• Tag the branch when the release is ready, which would trigger release on Dockerhub and proper release artifact on Github.
• Merge release branch into (thorugh the PR) into master and to develop