fix(ci): add per-file ignore in flake8 for A003

Author: heitorlessa

.flake8

@@ -6,6 +6,7 @@ max-complexity = 15
 per-file-ignores =
     tests/e2e/utils/data_builder/__init__.py:F401
     tests/e2e/utils/data_fetcher/__init__.py:F401
+    aws_lambda_powertools/utilities/data_classes/s3_event.py:A003 ; flake8-builtins isn't honouring inline ignore
 
 [isort]
 multi_line_output = 3