apperの[設定](非常にわかりにくいがPending Changesの右にドロップダウンメニュー)-[Check for new updates]:しない
で表示が止まったように見える
参考
debian - How to disable PackageKit software update password dialog? - Unix & Linux Stack Exchange
opening apper's settings menu I found this:
Apper configuration dialog
Setting this to Never took care of the problem for me.
以下未検証
systemctl mask packagekit works as well.
