software update pop up notification turn off

cf: https://askubuntu.com/questions/1237825/how-to-turn-off-software-updater-pop-up-notification

1. gsettings set com.ubuntu.update-notifier no-show-notifications true
2. Or use dconf-editor. Go to /com/ubuntu/update-notifier, and unclick  no-show-notification to false.

Check with:

 gsettings get com.ubuntu.update-notifier no-show-notifications

If shows true, done.