Google is changing all the names everything on its way. Yes, Google Keep app name is changed into Google Keep Notes.
It is unofficial though, the Google Keep APK on APKMirror shows the latest version as Google Keep Notes. The Play Store listing is still the same as similar to its older version and browser-based version too. But we expect that Google is changing all the names of its branded app since we already know Tez app has been literally changed its name into Google Pay worldwide. So this should happen on its way.
The changelog for the new app is,
* Support grid & ruled lines for drawings
* Bug fixes and performance improvements
Which doesn’t say about the name change, at this time we are unable to determine whether this happened in error or Google is actually planning for a name change. Let us wait for the official announcement from Google soon!