Fixing CODEOWNERS (#687)

### Description
Create a CODEOWNERS file with the current maintainers list. 

### Issues Resolved
N/A

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under the terms of the Apache 2.0 license.
For more information on following Developer Certificate of Origin and
signing off your commits, please check
[here](https://github.com/opensearch-project/OpenSearch/blob/main/CONTRIBUTING.md#developer-certificate-of-origin).

.github/workflows/CODEOWNERS

@@ -0,0 +1 @@
+* @idanl21 @ido-opster @dbason @swoehrl-mw @prudhvigodithi