Updating runCLI demo at wp-playground/cli README file (#2553)

## Motivation for the change, related issues The `runCLI` demo is showing an outdated demo; the flow using the runCLI has changed, and the example displayed at the latest playground package doesn't run. This pull request updates the demo with a simple example to spin a playground CLI server. This pull request is part of the issue #2552

Author: fellyph

packages/playground/cli/README.md

@@ -149,13 +149,16 @@ npx @wp-playground/cli@latest server --blueprint=./my-blueprint.json
 The Playground CLI can be controlled programmatically from your JavaScript code using the `runCLI` function. This allows you to integrate all CLI functionalities directly into your development workflow, for example, end-to-end testing.
 
 ```JavaScript
-import { runCLI } from "@wp-playground/cli";
+import { runCLI, RunCLIServer } from "@wp-playground/cli";
 
-const cliServer = await runCLI({
- command: "server"
+let cliServer: RunCLIServer;
+
+cliServer = await runCLI({
+ command: 'server',
+ php: '8.3',
+ wp: 'latest',
+ login: true
 });
-const handler = cliServer.requestHandler;
-const php = await handler.getPrimaryPhp();
 ```
 
 ## Comparisons