Update stale file regeneration to handle upb's CMakeLists.txt

The auto-updating of upb's CMakeLists.txt file broke with the upb merge but
will be fixed by this change.

PiperOrigin-RevId: 561005809

regenerate_stale_files.sh

@@ -16,6 +16,7 @@ readonly BazelBin="${BAZEL:-bazel} ${BAZEL_STARTUP_FLAGS}"
 ${BazelBin} test src:cmake_lists_staleness_test "$@" || ./bazel-bin/src/cmake_lists_staleness_test --fix
 ${BazelBin} test src/google/protobuf:well_known_types_staleness_test "$@" || ./bazel-bin/src/google/protobuf/well_known_types_staleness_test --fix
 ${BazelBin} test objectivec:well_known_types_staleness_test "$@" || ./bazel-bin/objectivec/well_known_types_staleness_test --fix
+(cd upb; ${BazelBin} test cmake:test_generated_files "$@" || ./bazel-bin/cmake/test_generated_files --fix)
 
 # Generate C# code.
 # This doesn't currently have Bazel staleness tests, but there's an existing