Add link to api doc (opensearch-project#169)

Signed-off-by: Philip May <philip@may.la>

Author: PhilipMay

README.md

@@ -11,6 +11,7 @@ OpenSearch Python Client
 
 - [Welcome!](#welcome)
 - [Getting Started](#getting-started)
+- [API Doc](https://opensearch-project.github.io/opensearch-py/)
 - [Compatibility with OpenSearch](#compatibility-with-opensearch)
 - [Project Resources](#project-resources)
 - [Code of Conduct](#code-of-conduct)
@@ -21,7 +22,7 @@ OpenSearch Python Client
 
 **opensearch-py** is [a community-driven, open source fork](https://aws.amazon.com/blogs/opensource/introducing-opensearch/)
 of elasticsearch-py licensed under the [Apache v2.0 License](https://github.com/opensearch-project/opensearch-py/blob/main/LICENSE.txt). 
-For more information, see [opensearch.org](https://opensearch.org/).
+For more information, see [opensearch.org](https://opensearch.org/) and the [API Doc](https://opensearch-project.github.io/opensearch-py/).
 
 This is the low-level client. A high-level Python client is in the works, and will be available soon.