add support for YAML or JSON

[mikesmullin]

Description

I think YAML is easier than JSON5, and I'd like the option to use either.

Test Case

Example using JS

{
  "type": "pie",
  "data": {
    "labels": [
      "Red",
      "Blue",
      "Yellow"
    ],
    "datasets": [
      {
        "data": [
          300,
          50,
          100
        ],
        "backgroundColor": [
          "#FF6384",
          "#36A2EB",
          "#FFCE56"
        ],
        "hoverBackgroundColor": [
          "#FF6384",
          "#36A2EB",
          "#FFCE56"
        ]
      }
    ]
  },
  "options": {}
}

Example using YAML

type: pie
data:
  labels:
  - Red
  - Blue
  - Yellow
  datasets:
  - data:
    - 300
    - 50
    - 100
    backgroundColor:
    - "#FF6384"
    - "#36A2EB"
    - "#FFCE56"
    hoverBackgroundColor:
    - "#FF6384"
    - "#36A2EB"
    - "#FFCE56"
options: {}

[mikesmullin]

This was necessary to launch & debug for me.

[mikesmullin]

Another example, from: https://www.chartjs.org/docs/latest/charts/line.html
See also: https://yaml.org/spec/1.2.0/#Preview

type: line
data:
  labels: [Jan, Feb, Mar, Apr, May, Jun, Jul]
  datasets:
  -
    label: My First Dataset
    data: [65, 59, 80, 81, 56, 55, 40]
    fill: false
    borderColor: rgb(75, 192, 192)
    tension: 0.1