Resolve "Automated build"
Closes #37 (closed)
Packaging, uploading the package and creating a gitlab release is now triggered by adding a new tag (not a release!). The release notes of the new tag MUST be empty.
Packaging and uploading should work. For now it points to the testpypi instance. After testing it from creating a test-tag, we can point the upload URL to the production instance of PyPI.