Update codeowners

Author: jimmyt857

.github/CODEOWNERS

@@ -8,9 +8,9 @@
 # Each line is a file pattern followed by one or more owners.
 
 # Global owners.
-* @jimmyt857 @Michael-Equi @uzhilinsky
+* @jimmyt857 @Michael-Equi @kvablack
 
-src/openpi/models/ @kvablack @uzhilinsky
-src/openpi/training/ @kvablack @uzhilinsky
+src/openpi/models/ @kvablack
+src/openpi/training/ @kvablack
 
-scripts/ @jimmyt857 @kvablack @uzhilinsky
+scripts/ @jimmyt857 @kvablack