fix: Unmarshal error on meroxa api --json

[raulb]

Reverts #169

---

--json already worked and only showing the body content as expected however #169 did caught an issue with arrays, which is what this pull-request is addressing.

before

❯ .m api get /v1/connectors --json
could not unmarshal: %!w(*json.UnmarshalTypeError=&{array 0x1500580 1  })
Error: json: cannot unmarshal array into Go value of type map[string]interface {}

now

❯ .m api get /v1/connectors --json
[
	{
		"id": 583,
		"name": "my-resource-149-954565",
		"type": "jdbc-source",
		"config": {},
		"state": "failed",
		"trace": "trace",
		"resource_id": 149,
		"pipeline_id": 11,
		"pipeline_name": "default",
		"streams": {
			"output": [
				"resource-149-942792-public.User"
			],
			"dynamic": false
		},
		"metadata": {
			"mx:connectorType": "source"
		},
		"created_at": "2021-04-29T13:34:32.66516Z",
		"updated_at": "2021-08-02T14:35:58.671148Z"
	}
]

[raulb]

However, #169 did capture an issue with unmarshaling arrays.

Here's a test on how it works for single objects:

❯ .m api get /v1/resources/149
> GET /v1/resources/149
< 200 OK HTTP/2.0
< Content-Length 414
< Meroxa-Request-Id 7088ef1d-cfc2-4d44-b367-401b3cb177b4
< Vary Origin
< Date Mon, 02 Aug 2021 13:43:41 GMT
< Content-Type application/json; charset=utf-8
{
	"id": 149,
	"uuid": "4430bf85-50d4-4b34-b979-b9668ecf8a35",
	"name": "your-resources",
	"type": "postgres",
	"url": "postgres://meroxa-demo.cwyhi7jl0lln.us-east-2.rds.amazonaws.com:5432/dboP24ThrN",
	"metadata": null,
	"connector_count": 1,
	"ssh_tunnel": null,
	"status": {
		"state": "ready",
		"details": "",
		"last_updated_at": "2021-06-14T15:04:13.384547Z"
	},
	"created_at": "2021-03-31T11:38:20.09416Z",
	"updated_at": "2021-06-03T08:05:57.684458Z"
}

cli on  revert-169-meroxa_api_fix [$!] via 🐹 v1.16.3 on ☁️  (us-east-1)
❯ .m api get /v1/resources/149 --json
{
	"connector_count": 1,
	"created_at": "2021-03-31T11:38:20.09416Z",
	"id": 149,
	"metadata": null,
	"name": "your-resources",
	"ssh_tunnel": null,
	"status": {
		"details": "",
		"last_updated_at": "2021-06-14T15:04:13.384547Z",
		"state": "ready"
	},
	"type": "postgres",
	"updated_at": "2021-06-03T08:05:57.684458Z",
	"url": "postgres://meroxa-demo.cwyhi7jl0lln.us-east-2.rds.amazonaws.com:5432/dboP24ThrN",
	"uuid": "4430bf85-50d4-4b34-b979-b9668ecf8a35"
}

This PR addresses the issue with arrays.

[lovromazgon]

LGTM (even though acceptance test is failing, but I checked and it's not even using this command, so I don't think it's related)