Even more PHP 8.1 deprecation fixes

Missed these two in the last release.

PHP 8.1 Deprecation Fixes

Just a couple of PHP 8.1 deprecation notices to deal with.

Guzzle 7 Support

This release allows Guzzle 7 and has been updated to use Guzzle 7 functions.

Note that the previous release that allowed Guzzle 7 (but didn't update the function calls) has been removed.

Fixing an issue with new version of OpenAPI Generator

Version 4.3.0 of OpenAPI Generator introduced an issue with query parameter serialization that affects our systems since we pass DateTime objects to some of these methods.

More details about the issue here: OpenAPITools/openapi-generator#7712

This release downgrades (and locks) OpenAPI Generator to 4.2.3 which doesn't have the issue.

Responses on POST methods

This adds support for parsing responses during POST operations, as well as updating to the latest version of the API documentation.

Initial Release

Openapi generator (#2)

* converting project to use openapi generator, adding all necessary generation steps to build.sh

* testing setting the produces on each request

* trying more defined response

* adding a data property that some endpoints have