update to OAS 2.36 and fix query param array format

[rdemarco-xero]

Description

Files API

• Adds getAssociationsCount method to the Files API

Payroll AU API

• Adds new property PaidLeaveEarnings to the OpeningBalance schema definition
• Adds new property PayOutType to the LeaveApplication and LeaveEarningsLine schema definitions

Release Notes

• getAssociationsCount enables developers to fetch a count of associations for a list of objects. Previously, developers had to call separately for each object.
• https://developer.xero.com/documentation/api/payrollau/stp-changes#opening-balance-paid-leave-earnings
• https://developer.xero.com/documentation/api/payrollau/stp-changes/#cashed-out-leave
• Includes fixes recommended in Bugfix/url length #331

Types of Changes

• Bug fix (non-breaking change that fixes an issue)
• New feature (non-breaking change that adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

[rdemarco-xero]

Hi @lancedfr, I implemented fixes in line with your PR #331.

I added some additional logic because String.join() doesn't work with a collection of UUIDs. Have a look and let me know what you think.