Update actions/upload-artifact action to v6

Author: renovate[bot]

.github/workflows/gradle.yml

@@ -69,7 +69,7 @@ jobs:
           GRADLE_ENTERPRISE_CACHE_PASSWORD: ${{ secrets.GRADLE_ENTERPRISE_CACHE_PASSWORD }}
 
       - name: Upload artifacts
-        uses: actions/upload-artifact@v4
+        uses: actions/upload-artifact@v6
         with:
             name: report
             path: |