Update Postgres MCP server reference link (supabase#36604)

The resource has been moved to an archived repo named `servers-archived`

Author: tk1ng

apps/docs/content/guides/getting-started/mcp.mdx

@@ -241,7 +241,7 @@ We recommend the following best practices to mitigate security risks when using
 
 ## MCP for local Supabase instances
 
-The Supabase MCP server connects directly to the cloud platform to access your database. If you are running a local instance of Supabase, you can instead use the [Postgres MCP server](https://github.com/modelcontextprotocol/servers/tree/main/src/postgres) to connect to your local database. This MCP server runs all queries as read-only transactions.
+The Supabase MCP server connects directly to the cloud platform to access your database. If you are running a local instance of Supabase, you can instead use the [Postgres MCP server](https://github.com/modelcontextprotocol/servers-archived/tree/main/src/postgres) to connect to your local database. This MCP server runs all queries as read-only transactions.
 
 ### Step 1: Find your database connection string