Update regex for coverage report in GitLab CI

The regular expression used to extract the coverage percentage from the coverage report was updated. Due to modified output format of pytest, the regex pattern was not working correctly. It has been changed to ensure accurate extraction.

.gitlab-ci.yml

@@ -5,7 +5,7 @@ pytest:
     - apt-get install -y python3-dev python3-pip graphviz graphviz-dev
     - pip install '.[test]'
     - pytest --cov --cov-report xml:coverage.xml
-  coverage: 'TOTAL.*\s+(\d+%)$'
+  coverage: '/TOTAL .*\s+(\d+%)$/'
   artifacts:
     reports:
       coverage_report: