Create a contact

curl --request POST \
  --url https://api.open.cx/contacts \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '{
  "contact": {
    "email": "jsmith@example.com",
    "phone": "<string>",
    "name": "<string>",
    "custom_data": {}
  }
}'

{
  "id": "3c90c3cc-0d44-4b50-8888-8dd25736052a"
}