Add zou3519 to CODEOWNERS for HOPs (pytorch#136679)

There are some tricky things that I want to guard against
Pull Request resolved: pytorch#136679
Approved by: https://github.com/Chillee

CODEOWNERS

@@ -98,6 +98,10 @@ test/test_type_promotion.py @mruberry
 test/functorch/test_ops.py @zou3519 @chillee @kshitij12345
 test/functorch/test_vmap.py @zou3519 @chillee @kshitij12345
 
+# HOPs
+torch/_higher_order_ops/*.py @zou3519
+torch/_dynamo/variables/higher_order_ops.py @zou3519
+
 # torch MPS
 test/test_mps.py @kulinseth @malfet
 aten/src/ATen/mps/ @kulinseth @malfet