feat(pep-561): Create py.typed file and include into pyproject.

Author: gmcrocetti

Diff for: aws_lambda_powertools/py.typed

@@ -3,6 +3,7 @@ name = "aws_lambda_powertools"
 version = "1.9.0"
 description = "Python utilities for AWS Lambda functions including but not limited to tracing, logging and custom metric"
 authors = ["Amazon Web Services"]
+include = ["aws_lambda_powertools/py.typed"]
 classifiers=[
     "Development Status :: 5 - Production/Stable",
     "Intended Audience :: Developers",