Add external plugin postgres-skills (#3743)

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

.github/plugin/marketplace.json

@@ -1494,6 +1494,33 @@
         "ref": "v2.1.0"
       }
     },
+    {
+      "name": "postgres-skills",
+      "description": "Expert PostgreSQL guidance and live database tools for Postgres anywhere, including local, self-hosted, containers, on-premises, AWS, Google Cloud, Azure Database for PostgreSQL, and Azure HorizonDB. Covers indexing, vector search and RAG, JSONB, partitioning, security, replication, and knowledge graphs with connection-aware guidance.",
+      "version": "0.1.2",
+      "author": {
+        "name": "Microsoft",
+        "url": "https://github.com/microsoft"
+      },
+      "repository": "https://github.com/microsoft/postgres-skills",
+      "homepage": "https://github.com/microsoft/postgres-skills",
+      "license": "MIT",
+      "keywords": [
+        "postgresql",
+        "database",
+        "azure",
+        "pgvector",
+        "rag",
+        "apache-age",
+        "graph"
+      ],
+      "source": {
+        "source": "github",
+        "repo": "microsoft/postgres-skills",
+        "path": "plugin",
+        "sha": "3ea7816fd1e449916b9277cc2671bc1c4c34f8c9"
+      }
+    },
     {
       "name": "power-apps-code-apps",
       "source": "plugins/power-apps-code-apps",