Fix Guzzle version to 7.2.0
Guzzle 7.3.0 introduces a breaking change after GuzzleHttp\Psr7\build_query()
was deprecated in favor of Query::build
.
This resulted in an error like:
PHP Fatal error: Uncaught Error: Call to undefined function GuzzleHttp\Psr7\build_query()
The SDK is generated by the OpenAPI Generator which still does not officially support Guzzle 7 and it's PHP template still uses build_query. Until this issue is fixed by the upstream provider we are locking the version of Guzzle to 7.2.0.
For more info see: OpenAPITools/openapi-generator#7869