Fix example in Getting Started docs. (#10)

The variable name was misspelt. Additionally, use collection expression syntax to simplify the example.

README.MD

@@ -54,8 +54,8 @@ var config = new McpServerConfig
         };
 		
 var factory = new McpClientFactory(
-            new[] { config },
-            _defaultOptions
+            [config],
+            options
         );
 ```