Update actions/upload-artifact action to v6

Author: renovate[bot]

.github/workflows/ci.yml

@@ -30,7 +30,7 @@ jobs:
 
     - name: Upload Test Results
       if: always()
-      uses: actions/upload-artifact@v4
+      uses: actions/upload-artifact@v6
       with:
         name: Test Results Linux
         path: '**/test-results/**/*.xml'