chore(deps): update actions/upload-artifact action to v6

Author: renovate[bot]

.github/workflows/ci.yml

@@ -34,7 +34,7 @@ jobs:
         run: mkdir staging && cp build/libs/*.jar staging
 
       - name: Upload a Build Artifact
-        uses: actions/upload-artifact@v5
+        uses: actions/upload-artifact@v6
         with:
           name: Preview Build (Do not report bugs for this build)
           path: staging