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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