Updated MAINTAINERS.md format (#668)

(cherry picked from commit ed94380)

MAINTAINERS.md

@@ -1,8 +1,11 @@
-# OpenSearch Machine Learning Maintainers
+## Overview
 
-## Maintainers
-| Maintainer | GitHub ID | Affiliation |
-| --------------- | --------- | ----------- |
-| Hanguang Zhang | [zhanghg08](https://github.com/zhanghg08) | Amazon |
-| Jing Zhang | [jngz-es](https://github.com/jngz-es) | Amazon |
-| Weicong Sun | [weicongs-amazon](https://github.com/weicongs-amazon) | Amazon |
+This document contains a list of maintainers in this repo. See [opensearch-project/.github/RESPONSIBILITIES.md](https://github.com/opensearch-project/.github/blob/main/RESPONSIBILITIES.md#maintainer-responsibilities) that explains what the role of maintainer means, what maintainers do in this and other repos, and how they should be doing it. If you're interested in contributing, and becoming a maintainer, see [CONTRIBUTING](CONTRIBUTING.md).
+
+## Current Maintainers
+
+| Maintainer     | GitHub ID                                             | Affiliation |
+| -------------- | ----------------------------------------------------- | ----------- |
+| Hanguang Zhang | [zhanghg08](https://github.com/zhanghg08)             | Amazon      |
+| Jing Zhang     | [jngz-es](https://github.com/jngz-es)                 | Amazon      |
+| Weicong Sun    | [weicongs-amazon](https://github.com/weicongs-amazon) | Amazon      |