Update codecov/codecov-action action to v6

Author: renovate[bot]

.github/workflows/ubuntu-maven.yml

@@ -45,7 +45,7 @@ jobs:
           mvn -B -fae -e test
 
       - name: Upload coverage to Codecov
-        uses: codecov/codecov-action@v5
+        uses: codecov/codecov-action@v6
         with:
           verbose: true
           token: ${{ secrets.CODECOV_TOKEN }}