Update numbers in README.md

Author: k0ekk0ek

README.md

@@ -25,15 +25,15 @@ similar performance boost for parsing zone data.
 Running `zone-bench` on my system (Intel Core i7-1065G7) against an older
 `.com` zone file of 12482791271 bytes under Linux (Fedora 37).
 
-GCC 12.2.1, release mode:
+clang version 15.0.7, release mode:
 ```
 $ time ./zone-bench parse ../../zones/com.zone
 Selected target haswell
 Parsed 341535548 records
 
-real    0m18.721s
-user    0m17.503s
-sys     0m1.181s
+real    0m16.344s
+user    0m15.125s
+sys     0m1.165s
 ```
 
 There are bound to be bugs and quite possibly smarter ways of implementing