install lcov_cobertura via pip

.gitlab-ci.yml

@@ -40,8 +40,8 @@ coverage-jdk11:
   stage: visualize
   image: python:3-slim
   script:
-    - curl https://raw.githubusercontent.com/eriwen/lcov-to-cobertura-xml/master/lcov_cobertura/lcov_cobertura.py > lcov2cobertura.py
-    - python lcov2cobertura.py target/coverage/lcov.info
+    - pip install lcov_cobertura
+    - python -m lcov_cobertura target/coverage/lcov.info
   needs: ["test1"]
   artifacts:
     reports: