Update GitHub workflow to use actions/upload-artifact v4 to fix deprecation

Author: osphvdhwj

.github/workflows/android-build.yml

@@ -35,7 +35,7 @@ jobs:
       run: ./gradlew assembleDebug
 
     - name: Upload APK artifact
-      uses: actions/upload-artifact@v3
+      uses: actions/upload-artifact@v4
       with:
         name: NewPipe-ExternalPlayer-APK
         path: external-player/build/outputs/apk/debug/external-player-debug.apk