Update Code for Publish for simpler workflow

[tobya]

I updated the code for publish so that it can be called with or without the 'domains' key

Both will work

$webflow->publishSite($siteId, ['domains' => ['mydomain.webflow.io', 'example.com']]);

$webflow->publishSite($siteId,['mydomain.webflow.io', 'example.com']);

Allow for a slightly more intuitive calling.

Additionally I have added a few more calls to the Readme.md to highlight other methods.