The api_key and api_id keys have been added to the hosts section in the config. If you have an existing published config file, add them to your config:
// 'connections' => [
// 'connectionName' => [
// 'hosts' => [
'api_id' => env('ELASTICSEARCH_API_ID', null),
'api_key' => env('ELASTICSEARCH_API_KEY', null),
// ],
// ],
// ],