将CSV转换为R中的自定义JSON格式

我想转换以下数据:

CERTIFICADO = tibble::tibble(type = "cuar_private_file",
                             title = "Certificado Participacion CC FECHIC 2023 30207",
                             excerpt = "Certificado Participacion CC FECHIC 2023 30207",
                             post_date = "2024-01-21 21:00:00",
                             owners = 1965,
                             attachments = "Certificado_Participacion_CC_FECHIC_2023_30207.pdf",
                             method = "copy")

转换为以下格式的JSON文件:

[
  {
    "type": "cuar_private_file",
    "title": "Certificado Participacion CC FECHIC 2023 30207",
    "excerpt": "Certificado de Participacion de Folio 30207 Cohorte FECHIC año 2023",
    "post_date": "2024-01-21 21:00:00",
    "owners": 
    { "usr": [1965]
    },
    "attachments":
    { "Certificado_Participacion_CC_FECHIC_2023_30207.pdf":
    { "method": "copy"
    }}
  }
]

我正在使用以下代码:

cat(toJSON(CERTIFICADO, pretty=TRUE), file = 'CERTIFICADO3.json')

但是这段代码给了我以下JSON文件:

[
  {
    "type": "cuar_private_file",
    "title": "Certificado Participacion CC FECHIC 2023 30207",
    "excerpt": "Certificado Participacion CC FECHIC 2023 30207",
    "post_date": "2024-01-21 21:00:00",
    "owners": 1965,
    "attachments": "Certificado_Participacion_CC_FECHIC_2023_30207.pdf",
    "method": "copy"
  }
]

为了获得我想要的JSON文件，我可以对代码进行什么调整？或者有其他方法可以做到这一点？

提前谢谢！