Update .github/CODEOWNERS

Co-authored-by: Stan Ulbrych <89152624+StanFromIreland@users.noreply.github.com>

Author: sethmlarson

.github/CODEOWNERS

@@ -133,6 +133,7 @@ Tools/check-c-api-docs/       @ZeroIntensity
 
 # Fuzzing
 Modules/_xxtestfuzz/                    @python/fuzzers
+Lib/test/test_xxtestfuzz.py             @python/fuzzers
 .github/workflows/reusable-cifuzz.yml   @python/fuzzers
 
 # Limited C API & Stable ABI