Copper6ssp: Add GVL vendor ID

[Copper6SSP]

doc - prebid/prebid.github.io#5727

[bsardo]

Verified

curl https://vendor-list.consensu.org/v3/vendor-list.json | jq '.vendors."1356"'
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100  646k  100  646k    0     0  2495k      0 --:--:-- --:--:-- --:--:-- 2504k
{
  "id": 1356,
  "name": "Copper6 LTD",
  "purposes": [
    1,
    3,
    4,
    5,
    6,
    7,
    8,
    9,
    10
  ],
  "legIntPurposes": [],
  "flexiblePurposes": [],
  "specialPurposes": [
    3
  ],
  "features": [
    3
  ],
  "specialFeatures": [
    1
  ],
  "cookieMaxAgeSeconds": 1209598,
  "usesCookies": true,
  "cookieRefresh": true,
  "urls": [
    {
      "langId": "en",
      "privacy": "https://www.copper6.com/privacy",
      "legIntClaim": "https://www.copper6.com/privacy"
    }
  ],
  "usesNonCookieAccess": false,
  "dataRetention": {
    "stdRetention": 14,
    "purposes": {},
    "specialPurposes": {}
  },
  "dataDeclaration": [
    1,
    2,
    8
  ],
  "deviceStorageDisclosureUrl": "https://ssp.copper6.com/deviceStorage.json"
}