Add codecoverage upload

Author: MDUYN

.github/workflows/test.yml

@@ -88,4 +88,12 @@ jobs:
       - name: Run tests
         run: |
           source .venv/bin/activate
-          coverage run -m unittest discover -s tests
+          coverage run -m unittest discover -s tests
+      #----------------------------------------------
+      #             upload coverage stats
+      #----------------------------------------------
+      - name: Upload coverage
+        uses: codecov/codecov-action@v3
+        with:
+          file: ./coverage.xml
+          fail_ci_if_error: true