Update upload-artifact to v4

Author: github-world192

.github/workflows/build-apk.yml

@@ -33,7 +33,7 @@ jobs:
         run: flutter build apk --release
 
       - name: Upload APK
-        uses: actions/upload-artifact@v3
+        uses: actions/upload-artifact@v4
         with:
           name: app-release
           path: build/app/outputs/apk/release/app-release.apk