Add 2.13 to version history (#6836)

Signed-off-by: Fanit Kolchina <kolchfa@amazon.com>
(cherry picked from commit 90ba1d6)
Signed-off-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>

_about/version-history.md

@@ -9,6 +9,7 @@ permalink: /version-history/
 
 OpenSearch version | Release highlights | Release date  
 :--- | :--- | :--- 
+[2.13.0](https://github.com/opensearch-project/opensearch-build/blob/main/release-notes/opensearch-release-notes-2.13.0.md) | Makes agents and tools and the OpenSearch Assistant Toolkit generally available. Introduces vector quantization within OpenSearch. Adds LLM guardrails and hybrid search with aggregations. Adds the Bloom filter skipping index for Apache Spark data sources, I/O-based admission control, and the ability to add an alerting cluster that manages all alerting tasks. For a full list of release highlights, see the Release Notes. | 2 April 2024
 [2.12.0](https://github.com/opensearch-project/opensearch-build/blob/main/release-notes/opensearch-release-notes-2.12.0.md) | Makes concurrent segment search and conversational search generally available. Provides an experimental OpenSearch Assistant Toolkit, including agents and tools, workflow automation, and OpenSearch Assistant for OpenSearch Dashboards UI. Adds a new match-only text field, query insights to monitor top N queries, and k-NN search on nested fields. For a full list of release highlights, see the Release Notes. | 20 February 2024
 [2.11.1](https://github.com/opensearch-project/opensearch-build/blob/main/release-notes/opensearch-release-notes-2.11.1.md) | Includes maintenance changes and bug fixes for cross-cluster replication, alerting, observability, OpenSearch Dashboards, index management, machine learning, security, and security analytics. For a full list of release highlights, see the Release Notes. | 30 November 2023
 [2.11.0](https://github.com/opensearch-project/opensearch-build/blob/main/release-notes/opensearch-release-notes-2.11.0.md) |  Adds multimodal and sparse neural search capability and the ability to take shallow snapshots that refer to data stored in remote-backed storage. Makes the search comparison tool generally available. Includes a simplified workflow to create threat detectors in Security Analytics and improved security in OpenSearch Dashboards. Experimental features include a new framework and toolset for distributed tracing and updates to conversational search. For a full list of release highlights, see the Release Notes. | 16 October 2023