Manage a subscription

curl -X POST https://api.einvoicing.dev/v1/billing/portal-sessions \  -H "Authorization: Bearer $EINVOICING_API_KEY"

<?php$client = new GuzzleHttp\Client();$response = $client->request('POST', 'https://api.einvoicing.dev/v1/billing/portal-sessions', [    'headers' => [        'Authorization' => 'Bearer ' . getenv('EINVOICING_API_KEY'),    ],]);$data = json_decode((string) $response->getBody(), true)['data'];

req, _ := http.NewRequest(http.MethodPost, "https://api.einvoicing.dev/v1/billing/portal-sessions", nil)req.Header.Set("Authorization", "Bearer "+os.Getenv("EINVOICING_API_KEY"))res, err := http.DefaultClient.Do(req)if err != nil {	log.Fatal(err)}defer res.Body.Close()

const res = await fetch("https://api.einvoicing.dev/v1/billing/portal-sessions", {  method: "POST",  headers: {    Authorization: `Bearer ${process.env.EINVOICING_API_KEY}`,  },});const { data } = await res.json();