Add external plugin elasticsearch (#1956)

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>

.github/plugin/marketplace.json

@@ -334,6 +334,32 @@
       "description": "Task Researcher and Task Planner for intermediate to expert users and large codebases - Brought to you by microsoft/edge-ai",
       "version": "1.0.0"
     },
+    {
+      "name": "elasticsearch",
+      "description": "Official Elastic plugin for GitHub Copilot — translate natural language to ES|QL queries, ingest data, manage Elasticsearch security (authn, authz, audit), and troubleshoot clusters. Powered by the official Elastic agent skills repository.",
+      "version": "0.3.0",
+      "author": {
+        "name": "Elastic",
+        "url": "https://www.elastic.co"
+      },
+      "repository": "https://github.com/elastic/agent-skills",
+      "homepage": "https://github.com/elastic/agent-skills/tree/main/plugins/elasticsearch",
+      "license": "Apache-2.0",
+      "keywords": [
+        "elasticsearch",
+        "esql",
+        "search",
+        "ingest",
+        "security",
+        "elastic"
+      ],
+      "source": {
+        "source": "github",
+        "repo": "elastic/agent-skills",
+        "path": "plugins/elasticsearch",
+        "sha": "e0d6b02194d4ec74cf9e5975290e950fc5ba549f"
+      }
+    },
     {
       "name": "ember",
       "source": "ember",