Add coverage collection to GitLab CI/CD.

.gitlab-ci.yml

@@ -12,6 +12,11 @@ test:
   script:
     - pip install -U tox
     - tox -e py38
+  artifacts:
+    reports:
+      coverage_report:
+        coverage_format: cobertura
+        path: coverage.xml
   rules:
     - if: ($CI_PIPELINE_SOURCE == "push") &&
           (($CI_COMMIT_BRANCH == "develop") || ($CI_COMMIT_BRANCH =~ "/^r\d\.\d+/"))
@@ -26,6 +31,11 @@ test-full:
   script:
     - pip install -U tox
     - tox -e py38 -- --fulltest
+  artifacts:
+    reports:
+      coverage_report:
+        coverage_format: cobertura
+        path: coverage.xml
   rules:
     - if: ($CI_PIPELINE_SOURCE == "merge_request_event") &&
           ($CI_MERGE_REQUEST_TITLE !~ /^Draft:.*/)