"A password reset request was sent..." System-level phishing?
I suggest changing your iCloud password and enabling 2-factor authentication if you haven't already.  But DO NOT click the notification to do this.  Go to Apple's website to do it.  (Also, don't trust anyone on the internet to give you a good link.  Check your URL bar to make sure you are at appleid.apple.com when you click even my link.)
Also, go to System Preferences -&gt; Notifications and see what apps have notification access and restrict notification access to anything that looks suspicious.
Judging by the way the notification looks, it does not look legitimate as it does not have an app icon.  You can call Apple if you want to make sure, though.