upload coverage to codecov with codecov-action

Author: chris48s

.github/workflows/test.yml

@@ -24,3 +24,6 @@ jobs:
       - name: Check Migrations are up-to-date
         run: docker-compose run -T --rm app ./manage.py makemigrations --check
         if: always()
+
+      - name: Upload coverage report to codecov
+        uses: codecov/codecov-action@v1