Test long_description using twine check

issue9781
review337181002

.drone.yml

@@ -17,6 +17,12 @@ pipeline:
             - tox -e "${TOXENV}"
         volumes:
              - cache:/root/.cache
+    check_dist:
+        image: ${IMAGE}
+        commands:
+            - pip install twine
+            - python setup.py sdist
+            - twine check dist/*
 
 matrix:
     include: