Show coverage report as action job summary

Closes #9

Author: dalito

.github/workflows/ci.yml

@@ -71,10 +71,12 @@ jobs:
         with:
           name: coverage-data
 
-      - name: Combine coverage and fail if less than threshold.
+      - name: Combine coverage, create reports and fail if less than threshold.
         run: |
           python -m coverage combine
-          python -m coverage html --skip-empty  # --skip-covered
+          python -m coverage html --skip-empty
+          echo '## Test Coverage Report\n' >> $GITHUB_STEP_SUMMARY
+          poetry run coverage report --format=markdown >> $GITHUB_STEP_SUMMARY
           python -m coverage report --fail-under=94
 
       - name: Upload HTML report