curl --request POST \
  --url https://api.example.com/link_to_registry \
  --header 'Authorization: Basic <encoded-value>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "ref": "<string>",
  "target": {
    "entity_name": "<string>",
    "portfolio_name": "<string>",
    "project_name": "<string>"
  },
  "aliases": []
}
'

{
  "version_index": 123
}