The answer is there is a newer Powershell console available which will likely replace the existing Powershell at some point and they're basically just advertising it. If you're not a scripter you can just ignore it.
For some backstory you have Windows PowerShell which is basically what all versions of Windows still come with and you have Powershell core which is indeed a cross-platform version which runs on Windows, Mac and Linux which is what Microsoft is shifting towards. Windows Powershell isn't developed any more except for security related patching if any. Windows Powershell ended at version 5.1. Powershell Core started with version 6.x and is now on 7.x with the newest version hitting about 91% compatibility with 5.1