Bump PHP Api Client to latest version

[robjmills]

Switch to latest release of BaseKit API Client package.

To test:

• create a sane .env file
• composer install
• php createSite.php

You should see something like

php createSite.php
Creating account and site
  Created account holder 1971
  Added package to account holder
  Created site 1973
  Found home page ref 12263
    Adding section image_text_2a
    Got upload token 80ca3a5ce5ad894874dea1884a5c43cb
    Got new asset url http://dg59kizslhdqr.cloudfront.net/ad/24/ad24658f-4afb-4fa8-a5c8-c060aa5f5d95.jpeg
    Updating widget ref 71100
    Updating widget ref 71103
    Updating widget ref 71105
    Updating widget ref 71107
    Adding section contact_3a
  Adding a new page
Done

[Copilot]

Pull Request Overview

This PR updates the BaseKit PHP API Client dependency from version 3.0.3 to 4.0.0, moving to the latest major release of the package.

• Bumps basekit/php-api-client from ^3.0.3 to ^4.0.0

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