Reenable release job on tags

Enables the release job again and addresses issue: #16 (closed)

It remove the except tag from the release job. This tag is and was preventing the docker image being build on release tag. I assume it was introduced to prevent a release if only examples have change with a new tagged version. In my understanding that is not what except is doing, it is preventing the job to be created if there is a change in the example folder. What might need to be done here is something like ignore the example folder on this job. But I have not idea how to configure this.

@nicholasklick, this removes a change you have introduced before and I am not sure if my assumption is right. Would be nice if you can comment on that!