Update codecov/codecov-action action to v4 (#432)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

.github/workflows/ci.yaml

@@ -32,7 +32,7 @@ jobs:
       - name: Run tests
         run: tox run -e unit
       - name: Upload Coverage to Codecov
-        uses: codecov/codecov-action@v3
+        uses: codecov/codecov-action@v4
 
   lib-check:
     name: Check libraries