fix: add json tag with lowercase

[mariajdab]

Now the response is:

{
   "transfers":{
      "received":[
         {
            "amount":10,
            "from":"d67350e531daa11c539b1f96de1487e9bc554082",
            "height":4,
            "txHash":"yfA0N4bjMxaFkWKaxhLc1Lm6qJW41AiHszaaXPmLBfA=",
            "timestamp":"2023-11-09T11:04:10.280248641-04:00",
            "to":"34e14abfe5052c4d81982cfaa43fdae3ec637901"
         },
         {
            "amount":80,
            "from":"c52d065a811cbc85aa232f010b42d883c1aa71f0",
            "height":1,
            "txHash":"IN87trSzT9AzKzCrA6Zl0WOZjsY/9BIrnYzQiIPgPJE=",
            "timestamp":"2023-11-09T11:04:10.252218421-04:00",
            "to":"34e14abfe5052c4d81982cfaa43fdae3ec637901"
         }
      ],
      "sent":[
         {
            "amount":25,
            "from":"34e14abfe5052c4d81982cfaa43fdae3ec637901",
            "height":3,
            "txHash":"Pd70tJAFtx6Q6tah4eFIVnGFGjEjoGDFd5xbcJZzFXs=",
            "timestamp":"2023-11-09T11:04:10.27257822-04:00",
            "to":"d67350e531daa11c539b1f96de1487e9bc554082"
         }
      ]
   }
}

[coveralls]

Pull Request Test Coverage Report for Build 6813695072

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.008%) to 61.782%

---

Totals
Change from base Build 6808960904:	0.008%
Covered Lines:	14593
Relevant Lines:	23620

---

💛 - Coveralls