Add TODO for updating public documentation

Signed-off-by: Bhumika Saini <[email protected]>

.github/pull_request_template.md

@@ -19,6 +19,7 @@ Resolves #[Issue number to be closed when this PR is merged]
   - [ ] New functionality has javadoc added
 - [ ] Commits are signed per the DCO using --signoff
 - [ ] Commit changes are listed out in CHANGELOG.md file (See: [Changelog](../blob/main/CONTRIBUTING.md#changelog))
+- [ ] GitHub issue/PR created in [OpenSearch documentation repo](https://github.com/opensearch-project/documentation-website) for the required public documentation changes (#[Issue/PR number])
 
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 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).