[FEATURE] `funding` field as array

[Scrum]

What / Why

Many have several services.

Example

"funding": [
    {
      "type": "opencollective",
      "url": "https://opencollective.com/<YOUR-COLLECTIVE>"
    },
    {
      "type": "patreon",
      "url": "https://patreon.com/<YOUR-COLLECTIVE>"
    },
    {
      "type": "github",
      "url": "https://github.com/sponsors/<YOUR-COLLECTIVE>"
    }
  ]

[ljharb]

@Scrum see npm/rfcs#68