⬆️ Update codecov/codecov-action action to v4

Author: renovate[bot]

.github/workflows/tests.yaml

@@ -71,4 +71,4 @@ jobs:
           poetry run coverage combine coverage*/.coverage*
           poetry run coverage xml -i
       - name: 🚀 Upload coverage report
-        uses: codecov/codecov-action@v3.1.6
+        uses: codecov/codecov-action@v4.0.0