Fresh install but guzzle's change to Query::build() not implemented

[sarahk]

ref: #249

This was pushed 2 years ago, so why is it not in a fresh install via composer?

The readme.md doc is dated 6 May '21 while the push discussion is September '21

[sarahk]

I'm a doofus, didn't realise the composer.json on the xero sample app was for a specific version and not >=