Stop using the preview API for 7.2 when the 7.2 rollout is complete

[rajbos]

Using it in all calls now, like here

Should be centralized for easy updates, and then the preview part can be removed from the version (when available). Seems like the EU org that I use for testing does not have it rolled out yet, so let's wait a week or so 🤞.

{
    "$id": "1",
    "innerException": null,
    "message": "The requested version \"7.2\" of the resource is under preview. The -preview flag must be supplied in the api-version for such requests. For example: \"7.2-preview\"",
    "typeName": "Microsoft.VisualStudio.Services.WebApi.VssInvalidPreviewVersionException, Microsoft.VisualStudio.Services.WebApi",
    "typeKey": "VssInvalidPreviewVersionException",
    "errorCode": 0,
    "eventId": 3000
}

The Advanced Security API's are not present in the docs yet: azure-devops-rest-7.2

[rajbos]

New namespace for the API (changed last week) has been added in Release 0.0.1.11.

Preview version is still needed.