Automate release in CI when a new tag is created
Since Gitlab 13.2 we can automatically create a new release when a tag is pushed.
For the description, we should look into placing it inside an environment variable in the job itself, and base that on the contents of the CHANGELOG. Maybe we'll need to adapt the CHANGELOG to a more suitable format so we can use some existing tools that can parse them.
Apart from that, it would be nice if we could upload the actual PHAR's generated as artifacts from the other pipelines and attach them as download to the description, but this is an added bonus.