Figure out how to release easily

[ewjoachim]

As of today we have

• 2 references to the current tag in README, which need to be commited before tagging
• 1 reference in the actions.yml, same
• The docker image is only pushed AFTER tagging
• There's also a reference to the tag on the example repo workflow
• There's a v1 branch which can also be used, which is the same as the tags. It feels like the v1 branch should target a v1 docker image ? Also we need to make it equal to the latest tag (should it be the default branch for the repo?)

The probability of forgetting something and botching a release is high.