See the link in another comment to report to Apple engineering - if enough people report the issue there’s always a chance it will be re-added in future iOS. Here’s what I said in my comment:
In previous iOS versions I was able to rate my music out of five stars with Siri. This was helpful when listening to music and the phone wasn’t in reach, or whilst out and about in extreme weather conditions when getting the phone out was not desirable. Please consider this feature in future iOS updates as I consider it to be basic functionality when it comes to the Apple Music app.