Return an array where each entry is an object with this form:

{ username: "beau", sources: ["fitbit", "runkeeper"] }

GET /api/public-data/sources-by-member/?offset=67600
HTTP 200 OK
Allow: GET, HEAD, OPTIONS
Cache-Control: max-age=0, no-cache, no-store, must-revalidate, private
Content-Type: application/json
Expires: Mon, 21 Apr 2025 05:13:19 GMT
Vary: Accept

{
    "count": 11726,
    "next": null,
    "previous": "https://www.openhumans.org/api/public-data/sources-by-member/?limit=100&offset=67500",
    "results": []
}