Update a VPN instance

curl --request PUT \
  --url https://api.altostrat.io/instances/{instance} \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '{
  "name": "<string>",
  "pushed_routes": [
    "<string>"
  ],
  "public_dns": [
    "127.0.0.1"
  ],
  "domains": [
    "<string>"
  ],
  "split_dns": [
    "<string>"
  ],
  "firewall": [
    {}
  ],
  "dns_custom": [
    {
      "name": "<string>",
      "type": "A",
      "value": "<string>"
    }
  ]
}'

{
  "id": "<string>",
  "name": "<string>",
  "region": "<string>",
  "hostname": "<string>",
  "configured": true,
  "rsa_ready": true,
  "diffie_hellman_ready": true,
  "server_ready": true,
  "status": [
    "<any>"
  ],
  "pushed_routes": [
    "<string>"
  ],
  "public_dns": [
    "127.0.0.1"
  ],
  "split_dns": [
    "<string>"
  ],
  "domains": [
    "<string>"
  ],
  "dns_custom": [
    {
      "name": "<string>",
      "type": "A",
      "value": "<string>"
    }
  ],
  "firewall": [
    {}
  ],
  "created_at": "2023-11-07T05:31:56Z"
}