Fix existing issue with mypy

Author: Pierre-Sassoulas

pylint/testutils/functional/lint_module_output_update.py

@@ -22,7 +22,9 @@ class TestDialect(csv.excel):
         delimiter = ":"
         lineterminator = "\n"
 
-    csv.register_dialect("test", TestDialect)
+    # TestDialect inherit from csv.excel, which inherit from Dialect
+    # probably something wrong in csv typing
+    csv.register_dialect("test", TestDialect)  # type: ignore[arg-type]
 
     def _check_output_text(
         self,