Add pip release procedure

.gitlab-ci.yml

@@ -89,3 +89,15 @@ pages:
     only:
         - tags
         - master
+
+
+pypi:
+    image: docker.km3net.de/base/python:3
+    stage: release
+    cache: {}
+    script:
+        - pip install -U twine
+        - python setup.py sdist
+        - twine upload dist/*
+    only:
+        - tags