Add tags to contact

curl --request POST \
  --url https://api.slant.app/v1/contacts/{contact_id}/tags \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "tag_ids": [
    "abc123",
    "def456"
  ]
}
'

{
  "tag_ids": [
    "<string>"
  ]
}