Correct copyright notices in README (opensearch-project#712)

Tommy Markley · web-flow · commit 64b3312f3bb8 · 2021-09-07T13:20:44.000-05:00
Resolves opensearch-project#711 Signed-off-by: Tommy Markley <markleyt@amazon.com>
diff --git a/README.md b/README.md
@@ -36,4 +36,4 @@ This project is licensed under the [Apache v2.0 License](LICENSE.txt).
 
 ## Copyright
 
-Copyright 2020-2021 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+Copyright OpenSearch Contributors. See [NOTICE](NOTICE.txt) for details.

Original file line number	Diff line number	Diff line change
`@@ -36,4 +36,4 @@ This project is licensed under the [Apache v2.0 License](LICENSE.txt).`
`36`	`36`
`37`	`37`	`## Copyright`
`38`	`38`
`39`		`-Copyright 2020-2021 Amazon.com, Inc. or its affiliates. All Rights Reserved.`
	`39`	`+Copyright OpenSearch Contributors. See [NOTICE](NOTICE.txt) for details.`