Document 4.0 breaking changes

[Matthew Chambers]

I ran into an issue where

\EasyPost\Shipment::create[
  'from_address' => $fromAddress,
  'to_address' => $toAddress,
  'parcel' => $parcel,
  'options' => [],
]);

with empty options now results in EasyPost\Error: The provided options are not valid.. This was not the case in 3.x using form encoding.

[Justin Hammond]

Thanks for reporting this @chamby, we'll take a look. In your testing, is it only options that has this problem or other objects too?

[Matthew Chambers]

This is the first instance that I ran into. This general pattern may appear elsewhere. I will update this issue when I have time for further testing next week. Thanks!