chore: exclude 'CODEOWNERS' from templated files

See: googleapis/synthtool#1201

Author: tseaver

owlbot.py

@@ -55,7 +55,10 @@
 # Add templated files
 # ----------------------------------------------------------------------------
 templated_files = common.py_library(microgenerator=True, split_system_tests=True,)
-s.move(templated_files, excludes=["docs/multiprocessing.rst", ".coveragerc"])
+s.move(
+    templated_files,
+    excludes=["docs/multiprocessing.rst", ".coveragerc", "CODEOOWNERS"],
+)
 
 python.py_samples(skip_readmes=True)