Add copyright claim

Author: DarcyRaynerDD

datadog_lambda/handler.py

@@ -1,5 +1,11 @@
+# Unless explicitly stated otherwise all files in this repository are licensed
+# under the Apache License Version 2.0.
+# This product includes software developed at Datadog (https://www.datadoghq.com/).
+# Copyright 2020 Datadog, Inc.
+
 from __future__ import absolute_import
 from importlib import import_module
+
 import os
 from datadog_lambda.wrapper import datadog_lambda_wrapper