Connect external issue

curl --request POST \
  --url https://api.incident.io/v2/follow_ups/{id}/actions/connect_external_issue \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "provider": "linear",
  "url": "https://linear.app/incident/issue/INC-123"
}
'

{
  "follow_up": {
    "assignee": {
      "email": "lisa@incident.io",
      "id": "01FCNDV6P870EA6S7TK1DSYDG0",
      "name": "Lisa Karlin Curtis",
      "role": "owner",
      "slack_user_id": "U02AYNF2XJM"
    },
    "assignee_team": {
      "id": "abc123",
      "name": "abc123"
    },
    "completed_at": "2021-08-17T13:28:57.801578Z",
    "created_at": "2021-08-17T13:28:57.801578Z",
    "creator": {
      "alert": {
        "id": "01GW2G3V0S59R238FAHPDS1R66",
        "title": "*errors.withMessage: PG::Error failed to connect"
      },
      "api_key": {
        "id": "01FCNDV6P870EA6S7TK1DSYDG0",
        "name": "My test API key"
      },
      "user": {
        "email": "lisa@incident.io",
        "id": "01FCNDV6P870EA6S7TK1DSYDG0",
        "name": "Lisa Karlin Curtis",
        "role": "owner",
        "slack_user_id": "U02AYNF2XJM"
      },
      "workflow": {
        "id": "01FCNDV6P870EA6S7TK1DSYDG0",
        "name": "My little workflow"
      }
    },
    "description": "Call the fire brigade",
    "external_issue_reference": {
      "issue_name": "INC-123",
      "issue_permalink": "https://linear.app/incident-io/issue/INC-1609/find-copywriter-to-write-up",
      "provider": "asana"
    },
    "id": "01FCNDV6P870EA6S7TK1DSYDG0",
    "incident_id": "01FCNDV6P870EA6S7TK1DSYDG0",
    "labels": [
      "bug",
      "urgent"
    ],
    "priority": {
      "description": "A follow-up that requires immediate attention.",
      "id": "01GNW4BAQ7XRMFF6FHKNXDFPRW",
      "name": "Urgent",
      "rank": 10
    },
    "status": "outstanding",
    "title": "Cat is stuck in the tree",
    "updated_at": "2021-08-17T13:28:57.801578Z"
  }
}