fix exclud-files

Author: jbrockmendel

Makefile

@@ -30,9 +30,9 @@ check:
 	python3 scripts/validate_unwanted_patterns.py \
 		--validation-type="private_import_across_module" \
 		--included-file-extensions="py" pandas/ \
-		--excluded-file-paths=pandas/tests/,asv_bench/
+		--excluded-file-paths=pandas/tests,asv_bench/,pandas/_vendored
 
 	python3 scripts/validate_unwanted_patterns.py \
 		--validation-type="private_function_across_module" \
 		--included-file-extensions="py" pandas/ \
-		--excluded-file-paths=pandas/tests/,asv_bench/
+		--excluded-file-paths=pandas/tests,asv_bench/,pandas/_vendored

scripts/validate_unwanted_patterns.py

@@ -35,6 +35,8 @@
     "_flex_comp_doc_FRAME",
     "_make_flex_doc",
     "_op_descriptions",
+    "_test_parse_iso8601",
+    "_json_normalize",  # TODO: remove after deprecation is enforced
     "_testing",
     "_test_decorators",
     "__version__",  # check np.__version__ in compat.numpy.function