Add report.html instead of coverage.xml to artifacts. Expire artifacts after 30 days.

.gitlab-ci.yml

@@ -30,11 +30,12 @@ test_py_tools_ds:
   artifacts:
     paths:
     - htmlcov/
-    - coverage.xml
+    - report.html
     - docs/_build/html/
     reports:
       cobertura: coverage.xml
       junit: report.xml
+    expire_in: 30 days
     when: always