correct code coverage generation step in CI

.gitlab-ci.yml

@@ -58,7 +58,7 @@ test-centos7:
   - coverage report
   - coverage html
   - 'mkdir -p ../public/$CI_COMMIT_REF_NAME'
-  - 'mv html ../public/$CI_COMMIT_REF_NAME/coverage' 
+  - 'mv htmlcov ../public/$CI_COMMIT_REF_NAME/htmlcov' 
   - pip3.6 install sphinx sphinx-argparse sphinxcontrib.bibtex sphinx_rtd_theme
   - cd docs
   - make html