try to fix coverage

.gitlab-ci.yml

@@ -39,7 +39,7 @@ testsuite:
     - pip install "git+https://i10git.cs.fau.de/pycodegen/pystencils.git@v2.0-dev"
     - pip install -e .
   script:
-    - pytest -v --cov-report html --cov-report xml --cov-report term --cov=src/pystencilssfg
+    - pytest -v --cov-report html --cov-report xml:coverage.xml --cov-report term --cov=src/pystencilssfg
   artifacts:
     when: always
     paths: