PUT /v1/sites/{siteId}/variables/{variableId} HTTP/1.1
Host: cloud.appwrite.io
Content-Type: application/json
X-Appwrite-Response-Format: 1.7.0
X-Appwrite-Project: <YOUR_PROJECT_ID>
X-Appwrite-Key: <YOUR_API_KEY>

{
  "key": "<KEY>",
  "value": "<VALUE>",
  "secret": false
}