add notice file (#191)

motivation: add notice for scripts that came from SwiftNIO

changes: add notice file

NOTICE.txt

@@ -0,0 +1,35 @@
+
+                            The SwiftAWSLambdaRuntime Project
+                            =================================
+
+Please visit the SwiftAWSLambdaRuntime web site for more information:
+
+  * https://github.com/swift-server/swift-aws-lambda-runtime
+
+Copyright 2017-2021 The SwiftAWSLambdaRuntime Project
+
+The SwiftAWSLambdaRuntime Project licenses this file to you under the Apache License,
+version 2.0 (the "License"); you may not use this file except in compliance
+with the License. You may obtain a copy of the License at:
+
+  https://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+License for the specific language governing permissions and limitations
+under the License.
+
+Also, please refer to each LICENSE.txt file, which is located in
+the 'license' directory of the distribution file, for the license terms of the
+components that this product depends on.
+
+-------------------------------------------------------------------------------
+
+
+This product contains a derivation various scripts from SwiftNIO.
+
+  * LICENSE (Apache License 2.0):
+    * https://www.apache.org/licenses/LICENSE-2.0
+  * HOMEPAGE:
+    * https://github.com/apple/swift-nio