List shifts

curl --request GET \
  --url https://api.rootly.com/v1/shifts \
  --header 'Authorization: Bearer <token>'

{
  "data": [
    {
      "id": "<string>",
      "type": "shifts",
      "attributes": {
        "schedule_id": "<string>",
        "rotation_id": "<string>",
        "starts_at": "<string>",
        "ends_at": "<string>",
        "is_override": true,
        "shift_override": {
          "data": {
            "id": "<string>",
            "type": "shift_override",
            "attributes": {
              "shift_id": "<string>",
              "created_by_user_id": 123,
              "created_at": "<string>",
              "updated_at": "<string>"
            }
          }
        },
        "user": {
          "data": {
            "id": "<string>",
            "type": "users",
            "attributes": {
              "email": "<string>",
              "created_at": "<string>",
              "updated_at": "<string>",
              "first_name": "<string>",
              "last_name": "<string>",
              "full_name": "<string>",
              "full_name_with_team": "<string>",
              "time_zone": "<string>"
            },
            "relationships": {
              "role": {
                "data": {
                  "id": "<string>",
                  "type": "roles"
                }
              },
              "on_call_role": {
                "data": {
                  "id": "<string>",
                  "type": "on_call_roles"
                }
              }
            }
          }
        }
      }
    }
  ]
}