I regularly get "UPDATE NOTICES"! Even when I try to look at Google Photos. The download is not from Abode and Mac OS warns against opening the download. Why does Google Photos STILL use FlashPlayer?
Either your computer is infected @Test Screen Name said or another app on your system like SmileBox is asking for Flash Player. Now that Flash Player is End of Life, it's not possible to download or update it. Therefore you should remove whichever app is asking for Flash Player.
Google Photos does not use Flash Player. Sounds as if you have an infected computer. FAKE update notices are a menace. Since Flash is dead, you know FOR SURE that the notices are fake. If you EVER responded to EVEN ONE of these, seek expert help in cleaning up your computer.